# Firmware version 2 # IOMOD Meter User Manual ### 1. Introduction IOMod Meter is a compact-sized stand-alone power meter for measuring analog AC input signals from low-power current and voltage sensors. It measures three phases of AC voltage and current amplitudes and phase shifts. Unlike IOMod 4Cs4Vs IOMod Meter only have three inputs for each phase current and voltage measurements. The measured and calculated values are transmitted to the host system via communication protocol **Modbus RTU, IEC 60870-5-101 or IEC 60870-5-103**. #### 1.1 Features - 3 AC current sensor inputs according to IEC 60044-8 (nominal value 225 mV); - 3 AC voltage sensor inputs according to IEC 60044-7 (nominal value 3.25/√3 V); - 32 samples per cycle; - FFT-based calculation with harmonic information; - Additional measurements of: - Frequency (Nominal frequencies: 50 and 60 Hz; Frequency range: 45–65 Hz); - Active, reactive, and apparent power; - Neutral voltage, neutral current; - Power factor; - Phase angle; - Firmware upgrade over USB, RS485; - Configurable using the IOMOD Utility app for user-friendly setup; - RS485 interface with a switchable terminating resistor; - Compact case with a removable transparent front panel; - DIN rail mounting for seamless integration into industrial systems; #### 1.2 Block diagram [![image-1740038444975.drawio.png](https://wiki.elseta.com/uploads/images/gallery/2025-02/scaled-1680-/image-1740038444975-drawio.png)](https://wiki.elseta.com/uploads/images/gallery/2025-02/image-1740038444975-drawio.png) Fig. 1.2.1. IOMOD Meter internal structure and block diagram ### 2. Hardware data #### 2.1 Mechanical drawings [![image-1738838645151.png](https://wiki.elseta.com/uploads/images/gallery/2025-02/scaled-1680-/image-1738838645151.png)](https://wiki.elseta.com/uploads/images/gallery/2025-02/image-1738838645151.png) Fig. 2.1.1. IOMOD Meter side view with dimensions and terminal description. 1 – current measurement inputs; 2 – voltage measurement inputs; 3 – ground input for analogue measurements; 4 - RS485 interface; 5 - power supply input [![image-1738838959320.png](https://wiki.elseta.com/uploads/images/gallery/2025-02/scaled-1680-/image-1738838959320.png)](https://wiki.elseta.com/uploads/images/gallery/2025-02/image-1738838959320.png) Fig. 2.1.2 IOMOD Meter front view with measurements #### 2.2 Terminal Connections IOMOD Meter has 18 terminals, which are depicted below: [![image-1738841460195.png](https://wiki.elseta.com/uploads/images/gallery/2025-02/scaled-1680-/image-1738841460195.png)](https://wiki.elseta.com/uploads/images/gallery/2025-02/image-1738841460195.png) Fig. 2.2.1 IOMOD Meter terminal diagram The description of each terminal can be found in the table below: Table 2.2.1 Terminal Specifications
**Terminal number** **Terminal name** **Description**
1 Ia Phase current 1
2 N
3 Ib Phase current 2 or neutral current in case of I0 metered mode
4 N
5 Ic Phase current 3
6 N
7 Ua Phase voltage 1 or phase current 1 in case of 3I3I connection mode
8 N
9 Ub Phase voltage 2 or phase current 2 in case of 3I3I connection mode, or neutral current in case of 3I3I connection mode along with I0 metered mode
10 N
11 Uc Phase voltage 3 or phase current 3 in case of 3I3I connection mode
12 N
13 COM Analogue measurements common neurtal terminals
14 COM
15 A RS485 interface port
16 B̄
17 V- Power source inputs
18 V+
#### 2.3 Status indication IOMOD Meter have 2 LEDs (Fig. 2.3.1), which indicate communication and power statuses. [![image-1738841815390.png](https://wiki.elseta.com/uploads/images/gallery/2025-02/scaled-1680-/image-1738841815390.png)](https://wiki.elseta.com/uploads/images/gallery/2025-02/image-1738841815390.png) Fig. 2.3.1. IOMOD Meter LEDs physical location The description of each IOMOD Meter LED can be found in the table below: Table 2.3.1. Description of LEDs.
**Name** **LED color** **Description**
RX/TX 🟢 (green) A blinking green light indicates active communication via the RS485 interface.
STAT 🟢 (green) The power source is connected to the power supply input.
🔵 (blue) IOMod Meter is connected to an external device via a USB mini cable.
### 3. Technical information Table 3.1. Technical specifications.
**System**
Dimension101 x 119 x 17.5 mm
CaseABS, black
Working environmentIndoor
Operating temperature-40°C ... +85°C
Recommended operating conditions 5–60°C and 20–80%RH;
ConfigurationUSB, RS485
Firmware upgradeUSB, RS485
**Electrical specifications**
Inputs Resolution 16 bits
Input resistance ~1 MΩ
Input capacitance < 170 pF
Input ranges ±10 V (amplitude)
Nominal values Current input: 225 mV (rms) Voltage input: 1.876 V (rms)
Overvoltage protection for all inputs up to ±20 V (amplitude)
**Power**
Power Supply9–33 VDC (full range)
Current consumption40 mA @ 12 VDC, 20 mA @ 24 VDC
### 4. Mounting and Installation #### 4.1 Connection Diagrams In this chapter the various options of connecting the device to medium-voltage systems are discussed. ##### 4.1.1 3 Low-Power Current Sensor, 3 Low-Power Voltage Sensors In the case of 3I3U connection mode IOMod Meter can be connected to a medium-voltage system by using low-power current and low-power voltage sensors (Fig. 4.1.1.1). In this scenario the neutral current I0 and the neutral voltage U0 are calculated by taking a vector sum of appropriate measurements. IOMod Meter GND inputs are not required to be connected to the neutral line because they are interconnected with signal neutral inputs (Fig. 1.2.1). [![image-1740043377566.png](https://wiki.elseta.com/uploads/images/gallery/2025-02/scaled-1680-/image-1740043377566.png)](https://wiki.elseta.com/uploads/images/gallery/2025-02/image-1740043377566.png) Fig. 4.1.1.1. Connection diagram with 3 low-power current and 3 low-power voltage sensors ##### 4.1.2 Fault Passage Indicator for two feeders The special feature of IOMod Meter is the ability to perform the metering of two feeders (Fig 4.1.2.1). In this case 3I3I connection mode needs to be enabled in [IOMod Utility](https://wiki.elseta.com/books/tools-and-software/page/iomod-utility) (Fig. 4.1.2.2). [![image-1740043505158.png](https://wiki.elseta.com/uploads/images/gallery/2025-02/scaled-1680-/image-1740043505158.png)](https://wiki.elseta.com/uploads/images/gallery/2025-02/image-1740043505158.png) Fig. 4.1.2.1. IOMod Meter connection diagram for two feeders [![image-1738845605650.png](https://wiki.elseta.com/uploads/images/gallery/2025-02/scaled-1680-/image-1738845605650.png)](https://wiki.elseta.com/uploads/images/gallery/2025-02/image-1738845605650.png) Fig. 4.1.2.2. IOMod Utility General settings tab with Connection mode set to 3I3I This mode allows us to use IOMod Meter voltage inputs for current measurements, so that the currents of both feeders are measured simultaneously. In the connection scheme above (Fig. 4.1.2.1) IOMod Meter each input is connected to the pair of feeders via low-power current sensors. ##### 4.1.3 3 Low-Power Voltage Sensor, 2 Phase Current, and Core Balance Current Transformer IOMod Meter allows directly measure the neutral current. In order to use this feature I0 current acquiring mode needs to be switched in [IOMod Utility](https://wiki.elseta.com/books/tools-and-software/page/iomod-utility) from calculated to metered (Fig. 4.1.3.1). [![image-1738845968961.png](https://wiki.elseta.com/uploads/images/gallery/2025-02/scaled-1680-/image-1738845968961.png)](https://wiki.elseta.com/uploads/images/gallery/2025-02/image-1738845968961.png) Fig. 4.1.3.1. IOMod Utility 3I3U settings view with I0 mode switched to metered After enabling I0 metered mode IOMod Meter second phase input (Ib+/N) becomes neutral current input. Since neutral current measurements are performed directly instead of being calculated it allows to achieve much higher precision and sensitivity. While neutral current being metered directly, the second phase measurements are being calculated by taking a vector sum of the measured currents. In the scheme below (Fig. 4.1.3.2) current and voltage measurements are taken by using low-power current and low-power voltage sensors. The second input (Ib+/N) is connected to a low-power current sensor which is placed on the neutral line. [![image-1740043531245.png](https://wiki.elseta.com/uploads/images/gallery/2025-02/scaled-1680-/image-1740043531245.png)](https://wiki.elseta.com/uploads/images/gallery/2025-02/image-1740043531245.png) Fig. 4.1.3.2. IOMod Meter I0 metered mode connection diagram ##### 4.1.4 2 Phase Current, and Core Balance Current Transformer for two feeders IOMod Meter operating in I0 metered mode preserves the ability of monitoring the currents of two feeders (Fig. 4.1.4.1). In this case 3I3I connection mode needs to be enabled in [IOMod Utility](https://wiki.elseta.com/books/tools-and-software/page/iomod-utility) (Fig. 4.1.4.2). 3I3I connection mode allows using voltage inputs as second channel current inputs. [![image-1740043554234.png](https://wiki.elseta.com/uploads/images/gallery/2025-02/scaled-1680-/image-1740043554234.png)](https://wiki.elseta.com/uploads/images/gallery/2025-02/image-1740043554234.png) Fig. 4.1.4.1. IOMod Meter connection diagram for two feeders with both channels I0 metered mode In the connection scheme above (Fig. 4.1.4.1) IOMod Meter current inputs are connected to the pair of feeders via low-power current sensors. Moreover, in [IOMod Utility](https://wiki.elseta.com/books/tools-and-software/page/iomod-utility) I0 mode of both current input channels needs to be changed from calculated to metered (Fig. 4.1.4.2). [![image-1738846533899.png](https://wiki.elseta.com/uploads/images/gallery/2025-02/scaled-1680-/image-1738846533899.png)](https://wiki.elseta.com/uploads/images/gallery/2025-02/image-1738846533899.png) Fig. 4.1.4.2. IOMod Utility 3I3I settings view with I0 mode of both channels set to metered ##### 4.1.5 Conventional Current transformers (CT) connection via CT adapters. IOMod Meter can take current measurements via a current transformer adapter (Fig. 4.1.5.1). Contrary to the current sensors, current transformers are usually intended for transforming priorly lowered currents from secondary distribution networks. [![image-1740043573316.png](https://wiki.elseta.com/uploads/images/gallery/2025-02/scaled-1680-/image-1740043573316.png)](https://wiki.elseta.com/uploads/images/gallery/2025-02/image-1740043573316.png) Fig. 4.1.5.1. IOMod Meter connection diagram with current transformer adapter and low-power voltage sensors ##### 4.1.6 Conventional Voltage transformers (VT) connection via VT adapters. IOMod Meter is able to take voltage measurements via a voltage transformer adapter (Fig. 4.1.6.1). Contrary to the voltage sensors, voltage transformers are usually intended for transforming priorly lowered voltages from secondary distribution networks. [![image-1740043586442.png](https://wiki.elseta.com/uploads/images/gallery/2025-02/scaled-1680-/image-1740043586442.png)](https://wiki.elseta.com/uploads/images/gallery/2025-02/image-1740043586442.png) Fig. 4.1.6.1. IOMod Meter connection diagram with low-power current sensors and voltage transformer adapter #### 4.2 RS485 Interface IOMod Meter has an integrated 120 Ω termination resistor, which can be enabled or disabled via the configuration terminal. It is recommended that termination be used at each end of the RS485 cable. IOMod Meter has a 1/8 Unit load receiver, allowing up to 255 units on a single line (compared to standard 32 units). To reduce reflections keep the stubs (cable distance from the main RS485 bus line) as short as possible. #### 4.3 Power Supply IOMOD Meter need to be powered by a 9–33 V power source. IOMOD Meter power supply inputs are located next to RS485 interface inputs (Fig 4.3.1). [![image-1738847702757.png](https://wiki.elseta.com/uploads/images/gallery/2025-02/scaled-1680-/image-1738847702757.png)](https://wiki.elseta.com/uploads/images/gallery/2025-02/image-1738847702757.png) Fig. 4.3.1. Power supply inputs physical location #### 4.4 USB Connection IOMOD Meter device has a USB-mini connection port. Its primary function is the physical connection establishment between the IOMOD and a PC. By selecting the USB interface and correct communication port in [IOMod Utility](https://wiki.elseta.com/books/tools-and-software/page/iomod-utility) (Fig. 4.4.1) a user can connect to the IOMOD to control its parameters and monitor its measured data and the status of fault detection functions. Also, this connection can be used for powering the module. ![](https://wiki.elseta.com/uploads/images/gallery/2025-02/embedded-image-aekeuifq.png) Fig. 4.4.1. IOMOD Utility interface and communication port parameters [![image-1738849420377.png](https://wiki.elseta.com/uploads/images/gallery/2025-02/scaled-1680-/image-1738849420377.png)](https://wiki.elseta.com/uploads/images/gallery/2025-02/image-1738849420377.png) Fig. 4.4.2. IOMOD Meter USB connection port physical location ### 5. Parametrization In this section, the IOMOD Meter settings configuration is described. IOMod Meter configuration is performed via IOMod Utility (the manual can be accessed [here](https://wiki.elseta.com/books/tools-and-software/page/iomod-utility)). All IOMOD-related settings can be found in the "Iomod settings" tab (Fig. 5.1). ![](https://wiki.elseta.com/uploads/images/gallery/2025-02/embedded-image-qjzixxgh.png) Fig. 5.1. IOMod settings tab #### 5.1 General Parameters To configure IOMOD Meter general settings open the "Iomod settings" tab in IOMOD Utility. After clicking on "Iomod settings", the "General" section opens (Fig. 5.1.1). [![image-1738849875787.png](https://wiki.elseta.com/uploads/images/gallery/2025-02/scaled-1680-/image-1738849875787.png)](https://wiki.elseta.com/uploads/images/gallery/2025-02/image-1738849875787.png) Fig. 5.1.1. IOMOD Utility with IOMOD Meter general settings window opened The general settings consist of two parameters, which apply to all communication protocols (Table 5.1.1). "Measurands set" and "Scale factor" are defined only in the context of the IEC 60870-5-103 communication protocol. The last parameter "Value update time (ms)" is defined only in the context of IEC 60870-5-101 and IEC 60870-5-103 communication protocols. Table 5.1.1. IOMOD Meter general parameter ranges and default values.
**Parameter** **Range** **Default value**
Connection mode 3I3I, 3I3U 3I3U
Frequency 50 Hz, 60 Hz 50 Hz
Value update time (ms) \* 20-60000 500
Measurands set \*\* 1-4 1
Scale factor \*\* 1.2, 1.4 1.2
*\*The parameter is defined only for IEC 60870-5-101 and IEC 60870-5-103 communication protocols.* *\*\* The parameters are defined only for the IEC 60870-5-103 communication protocol.* The first parameter "Connection mode" allows us to define how the values measured with voltage inputs (terminals 7–12, see Fig. 2.2.1) are supposed to be interpreted. The values are interpreted as voltage measurements by default. This connection mode is denoted by the 3I3U designation. 3I3U designation means – "3 currents and 3 voltages" meaning that both current and voltage measurements are being taken from a feeder. 3I3U connection mode parameters can be found in a separate settings section which is labelled with communication mode designation (connection mode settings are described in the next section). Selecting 3I3I connection mode in IOMOD Utility changes IOMOD Setting sections – 3I3U changes to 3I3I. IOMOD Meter, in 3I3I connection mode, interprets the values measured with voltage inputs (terminals 7–12, see Fig. 2.2.1) as current measurements. 3I3I designation means – "3 currents and 3 currents" meaning that the voltage inputs become the second channel current inputs. The 3I3I settings section allows us to modify connection mode parameters (described in the next section). The "Frequency" parameter allows us to set the nominal frequency of the power line to which IOMOD Meter is connected. If the IEC 60870-5-103 communication protocol is selected, the "Measurands set" parameter sets one of the lists of measurements (Table 6.3.2, Table 6.3.3) which is going to be sent to a master device. If the IEC 60870-5-103 communication protocol is selected, the "Scale factor" parameter sets a value by which all measurements are going to be multiplied. The value update time (ms) parameter defines how frequently the updated values are going to be sent to a controlling station via IEC 60870-5-101 or IEC 60870-5-103 communication protocols. #### 5.2 Connection mode settings As was described early IOMOD Meter supprots two connection modes – 3I3U and 3I3I. After selecting one of them in General settings (Fig. 5.1.1) a new respectively named section appears. In this subsection, the parameters of a certain connection mode are going to be described. ##### 5.2.1 3I3U connection mode parameters The 3I3U connection mode parameters section has six parameters (Table 5.2), which are going to be described below. Table 5.2.1.1 3I3U connection mode parameters.
**Parameter** **Range** **Default value**
Primary current (A) 1–2000 100
Primary voltage (kV) 0.2–60.0 10.0
Current sensor (mV) 100–300 225
Voltage sensor (V) 1.0–3.0 1.876
I0 mode Calculated, Metered Calculated
Primary current I0 1–2000 100
- The "Primary current (A)" parameter defines the nominal input current of a current sensor or a current transformer. - The "Primary voltage (kV)" parameter sets the nominal input line voltage of a voltage sensor or a voltage transformer. If instead of the line voltage, the sensor or adapter converts the phase voltage, still the value of the line voltage must be used. For example, if a voltage sensor declares the primary voltage of 10/√3 kV, then 10 kV must be used for the "Primary voltage (kV)" parameter, for it is the line voltage of the network. - The "Current sensor (mV)" parameter defines the nominal output voltage of a current sensor or a current transformer. - The "Voltage sensor (V)" parameter defines the nominal output phase voltage of a voltage sensor or a voltage transformer. Contrary to the Primary Voltage, the phase voltage must be used for this parameter. For example, if a voltage sensor declares the secondary voltage of 3.25/√3 V, then the approximate phase voltage value must be used. It means, that the given expression must be evaluated (3.25/√3 ≈ 1.876 V) and the result must be entered into the "Voltage sensor (V)" parameter (1.876 V). - The "I0 mode" parameter defines the way of obtaining the neutral current values. The default parameter value is "Calculated", meaning that the value of the neutral current is going to be calculated by taking the phase current measurements. If "Metered" is selected, then the neutral current values are expected to be measured directly. - The "Primary current I0" parameter defines the nominal input neutral current which is being measured by a Core Balance Current Transformer. ##### 5.2.2 3I3I connection mode parameters The 3I3I connection mode parameters section has eight parameters (Table 5.3), which are going to be described below. Table 5.2.2.1 3I3I connection mode parameters.
**Parameter** **Range** **Default value**
Primary current ch1 (A) 1–2000 100
Primary current ch2 (A) 1–2000 100
Current sensor ch1 (mV) 100–300 225
Current sensor ch2 (mV) 100–300 225
I0 mode ch1 Calculated, Metered Calculated
I0 mode ch2 Calculated, Metered Calculated
Primary current I0 ch1 1–2000 100
Primary current I0 ch2 1–2000 100
- The "Primary current ch1 (A)" parameter sets the nominal input current of a current sensor or a current transformer which is connected to the first channel current inputs. - The "Primary current ch2 (A)" parameter sets the nominal input current of a current sensor or a current transformer which is connected to the second channel current inputs. - The "Current sensor ch1 (mV)" parameter defines the nominal output voltage of a current sensor or a current transformer which is connected to the first channel current inputs. - The "Current sensor ch2 (mV)" parameter defines the nominal output voltage of a current sensor or a current transformer which is connected to the second channel current inputs. - The "I0 mode ch1" parameter defines the way of obtaining the neutral current values with the first channel current inputs. The default parameter value is "Calculated", meaning that the value of the neutral current is going to be calculated by taking the phase current measurements. If "Metered" is selected, then the neutral current values are expected to be measured directly. - The "I0 mode ch2" parameter defines the way of obtaining the neutral current values with the second channel current inputs. The default parameter value is "Calculated", meaning that the value of the neutral current is going to be calculated by taking the phase current measurements. If "Metered" is selected, then the neutral current values are expected to be measured directly. - The "Primary current I0 ch1" parameter defines the nominal input neutral current which is being measured by a Core Balance Current Transformer connected to the first channel current inputs. - The "Primary current I0 ch2" parameter defines the nominal input neutral current which is being measured by a Core Balance Current Transformer connected to the second channel current inputs. #### 5.3 Data Select The data select tab (Fig. 5.3.1) is the last IOMOD settings section, which provides a way to control the data being sent via the IEC 60870-5-101 communication protocol. The IOA (Information Object Address) of each data unit is specified in the brackets to the right of a parameter's name. To include a parameter to a set of parameters which are sent via IEC 60870-5-101 communication protocol a checkbox to the right of a parameter's name needs to be checked. [![image-1738917577097.png](https://wiki.elseta.com/uploads/images/gallery/2025-02/scaled-1680-/image-1738917577097.png)](https://wiki.elseta.com/uploads/images/gallery/2025-02/image-1738917577097.png) Fig. 5.3.1. IOMOD Meter Data select tab view #### 5.4 Diagnostics The IOMOD Utility Diagnostics tab allows real-time monitoring of IOMOD Meter measurements and harmonics statuses. The diagnostics mode of both measurements and harmonics is turned off by default. This is indicated by the red "Offline" word designation and by the unchanging black circle (Fig. 5.4.1, Fig. 5.4.2). [![image-1738918161285.png](https://wiki.elseta.com/uploads/images/gallery/2025-02/scaled-1680-/image-1738918161285.png)](https://wiki.elseta.com/uploads/images/gallery/2025-02/image-1738918161285.png) Fig. 5.4.1. IOMOD Utility Diagnostics tab Measurements section in offline mode [![image-1738918112988.png](https://wiki.elseta.com/uploads/images/gallery/2025-02/scaled-1680-/image-1738918112988.png)](https://wiki.elseta.com/uploads/images/gallery/2025-02/image-1738918112988.png) Fig. 5.4.2 IOMOD Utility DIganostics tab Harmonics section in offline mode To turn on real-time monitoring of both Diagnostics sections, the "Connect" button to the left of the "Offline" word designation needs to be pressed. The button can be pressed in either the Diagnostics sections (Measurements or Harmonics). After pressing the "Connect" button the word designation of Diagnostics mode changes to "Online", the black circle starts blinking and the button name changes to "Disconnect". It is advisable to turn off Diagnostics mode before setting new IOMOD Meter parameters. To turn off Diagnostics real-time monitoring mode, the "Disconnect" button needs to be pressed. ### 6. Communication Protocols IOMOD Meter supports three communication protocols: Modbus RTU, IEC 60870-5-101 and IEC 60870-5-103. Using these communication protocols a user via a master device can read the measured data from the device. The communication protocol can be selected using IOMOD Utility (IOmod Utility manual can be accessed [here](https://wiki.elseta.com/books/tools-and-software/page/iomod-utility)). #### 6.1 Modbus RTU operational information When the Modbus RTU protocol is selected IOMOD Meter acts as a slave device and waits for requests from the Modbus master. For reading the measurements, a master can send a Read Input Register (FC 04) request. Request with an unsupported function code or register number out of range will be answered with the corresponding exception. Measurement results in nominal values having an integer type, while results in primary values are 32-bit float type. Table 6.1.1 Nominal values in integer format. The data can be read using Modbus FC4 request.
**Address** **(Dec)** **Description** **Units** **Data type** **Access**
0 Phase L1 current % x10 UINT16 R
1 Phase L2 current % x10 UINT16 R
2 Phase L3 current % x10 UINT16 R
3 Calculated neutral current % x10 UINT16 R
4 Calculated line voltage U12 % x10 UINT16 R
5 Calculated line voltage U23 % x10 UINT16 R
6 Calculated line voltage U31 % x10 UINT16 R
7 Calculated zero sequence voltage % x10 UINT16 R
8 Total 3 phase apparent power (S1+S2+S3) % x10 UINT16 R
9 Total 3 phase active power (P1+P2+P3) % x10 INT16 R
10 Total 3 phase reactive power (Q1+Q2+Q3) % x10 INT16 R
11 Total 3-phase power factor x1000 INT16 R
12 Total harmonic distortions of U1 voltage UINT16 R
13 Total harmonic distortions of U2 voltage UINT16 R
14 Total harmonic distortions of U3 voltage UINT16 R
15 Total harmonic distortions of I1 current UINT16 R
16 Total harmonic distortions of I2 current UINT16 R
17 Total harmonic distortions of I3 current UINT16 R
18 3rd harmonic level of the I1 current % UINT16 R
19 5th harmonic level of I1 current % UINT16 R
20 7th harmonic level of I1 current % UINT16 R
21 9th harmonic level of I1 current % UINT16 R
22 3rd harmonic level of the I2 current % UINT16 R
23 5th harmonic level of I2 current % UINT16 R
24 7th harmonic level of I2 current % UINT16 R
25 9th harmonic level of I2 current % UINT16 R
26 3rd harmonic level of the I3 current % UINT16 R
27 5th harmonic level of I3 current % UINT16 R
28 7th harmonic level of I3 current % UINT16 R
29 9th harmonic level of I3 current % UINT16 R
30 3rd harmonic level of U1 voltage % UINT16 R
31 5th harmonic level of U1 voltage % UINT16 R
32 7th harmonic level of U1 voltage % UINT16 R
33 9th harmonic level of U1 voltage % UINT16 R
34 3rd harmonic level of U2 voltage % UINT16 R
35 5th harmonic level of U2 voltage % UINT16 R
36 7th harmonic level of U2 voltage % UINT16 R
37 9th harmonic level of U2 voltage % UINT16 R
38 3rd harmonic level of U3 voltage % UINT16 R
39 5th harmonic level of U3 voltage % UINT16 R
40 7th harmonic level of U3 voltage % UINT16 R
41 9th harmonic level of U3 voltage % UINT16 R
42 Phase L1 active power % x10 INT16 R
43 Phase L2 active power % x10 INT16 R
44 Phase L3 active power % x10 INT16 R
45 Phase L1 reactive power % x10 INT16 R
46 Phase L2 reactive power % x10 INT16 R
47 Phase L3 reactive power % x10 INT16 R
48 The phase angle of U1 voltage 0.1 deg INT16 R
49 The phase angle of U2 voltage 0.1 deg INT16 R
50 The phase angle of U3 voltage 0.1 deg INT16 R
51 Phase L1 voltage % x10 UINT16 R
52 Phase L2 voltage % x10 UINT16 R
53 Phase L3 voltage % x10 UINT16 R
54 Frequency of phase L1 voltage Hz x100 UINT16 R
55 Input I4 current % x10 UINT16 R
56 Input U4 voltage % x10 UINT16 R
57 S1 phase apparent power % x10 INT16 R
58 S2 phase apparent power % x10 INT16 R
59 S3 phase apparent power % x10 INT16 R
60 L1 phase power factor % x10 INT16 R
61 L2 phase power factor % x10 INT16 R
62 L3 phase power factor % x10 INT16 R
63 The angle of the I1 current 0.1 deg INT16 R
64 The angle of the I2 current 0.1 deg INT16 R
65 The angle of the I3 current 0.1 deg INT16 R
66 Line voltage U12 angle 0.1 deg INT16 R
67 Line voltage U23 angle 0.1 deg INT16 R
68 Line voltage U31 angle 0.1 deg INT16 R
69 Current positive sequence Data \* 10 UINT16 %
70 Current negative sequence % x10 UINT16 R
71 Voltage positive sequence % x10 UINT16 R
72 Voltage negative sequence % x10 UINT16 R
73 Current I0 angle 0.1 deg UINT16 R
74 Current I4 angle 0.1 deg UINT16 R
75 Voltage U0 angle 0.1 deg UINT16 R
76 Voltage U4 angle 0.1 deg UINT16 R
77 Current Ip angle 0.1 deg UINT16 R
78 Current In angle 0.1 deg UINT16 R
79 Current Up angle 0.1 deg UINT16 R
80 Current Un angle 0.1 deg UINT16 R
81 Current I1 2nd harmonic % x10 UINT16 R
82 Current I2 2nd harmonic % x10 UINT16 R
83 Current I3 2nd harmonic % x10 UINT16 R
84 Current I1 channel 2 % x10 UINT16 R
85 Current I2 channel 2 % x10 UINT16 R
86 Current I3 channel 2 % x10 UINT16 R
87 Current I0 channel 2 % x10 UINT16 R
88 Current I4 channel 2 % x10 UINT16 R
89 Current Ip channel 2 % x10 UINT16 R
90 Current In channel 2 % x10 UINT16 R
91 Current I1 channel 2 angle 0.1 deg UINT16 R
92 Current I2 channel 2 angle 0.1 deg UINT16 R
93 Current I3 channel 2 angle 0.1 deg UINT16 R
94 Current I0 channel 2 angle 0.1 deg UINT16 R
95 Current I4 channel 2 angle 0.1 deg UINT16 R
96 Current Ip channel 2 angle 0.1 deg UINT16 R
97 Current In channel 2 angle 0.1 deg UINT16 R
98 Current I1 2nd harmonic channel 2 0.1 deg UINT16 R
99 Current I2 2nd harmonic channel 2 0.1 deg UINT16 R
100 Current I3 2nd harmonic channel 2 0.1 deg UINT16 R
101 THD of current I1 channel 2 UINT16 R
102 THD of current I2 channel 2 UINT16 R
103 THD of current I3 channel 2 UINT16 R
104 Current I1 3rd harmonic channel 2 % UINT16 R
105 Current I1 5th harmonic channel 2 % UINT16 R
106 Current I1 7th harmonic channel 2 % UINT16 R
107 Current I1 9th harmonic channel 2 % UINT16 R
108 Current I2 3rd harmonic channel 2 % UINT16 R
109 Current I2 5th harmonic channel 2 % UINT16 R
110 Current I2 7th hamonic channel 2 % UINT16 R
111 Current I2 9th harmonic channel 2 % UINT16 R
112 Current I3 3rd harmonic channel 2 % UINT16 R
113 Current I3 5th harmonic channel 2 % UINT16 R
114 Current I3 7th harmonic channel 2 % UINT16 R
115 Current I3 9th harmonic channel 2 % UINT16 R
116-117 Active import energy kWh UINT32 R
118-119 Active export energy kWh UINT32 R
120-121 Reactive import energy kVArh UINT32 R
122-123 Reactive export energy kVArh UINT32 R
Table 6.1.2 Primary values in float format. The data can be read using Modbus FC4.
**Address (Dec)** **Description** **Units** **Data type** **Access**
200 - 201 Current I1 A FLOAT R
202 - 203 Current I2 A FLOAT R
204 - 205 Current I3 A FLOAT R
206 - 207 Current I0 A FLOAT R
208 - 209 Voltage U12 U FLOAT R
210 - 211 Voltage U23 U FLOAT R
212 - 213 Voltage U31 U FLOAT R
214 - 215 Voltage U1 U FLOAT R
216 - 217 Voltage U2 U FLOAT R
218 - 219 Voltage U3 U FLOAT R
220 - 221 Voltage U0 U FLOAT R
222 - 223 Voltage U1 angle ° FLOAT R
224 - 225 Voltage U2 angle ° FLOAT R
226 - 227 Voltage U3 angle ° FLOAT R
228 - 229 Apparent power Σ3 phase VA FLOAT R
230 - 231 Active power Σ3 phase W FLOAT R
232 - 233 Reactive power Σ3 phase Var FLOAT R
234 - 235 Power factor Σ3 phase FLOAT R
236 - 237 Apparent power S1 VA FLOAT R
238 - 239 Apparent power S2 VA FLOAT R
240 - 241 Apparent power S3 VA FLOAT R
242 - 243 Active power P1 W FLOAT R
244 - 245 Active power P2 W FLOAT R
246 - 247 Active power P3 W FLOAT R
248 - 249 Reactive power Q1 Var FLOAT R
250 - 251 Reactive power Q2 Var FLOAT R
252 - 253 Reactive power Q3 Var FLOAT R
254 - 255 Power factor PF1 FLOAT R
256 - 257 Power factor PF2 FLOAT R
258 - 259 Power factor PF3 FLOAT R
260 - 261 Frequency Hz FLOAT R
262 - 263 THD Voltage U1 FLOAT R
264 - 265 THD Voltage U2 FLOAT R
266 - 267 THD Voltage U3 FLOAT R
268 - 269 THD Current I1 FLOAT R
270 - 271 THD Current I2 FLOAT R
272 - 273 THD Current I3 FLOAT R
274 - 275 Current I1 3rd harmonic FLOAT R
276 - 277 Current I1 5th harmonic FLOAT R
278 - 279 Current I1 7th harmonic FLOAT R
280 - 281 Current I1 9th harmonic FLOAT R
282 - 283 Current I2 3rd harmonic FLOAT R
284 - 285 Current I2 5th harmonic FLOAT R
286 - 287 Current I2 7th harmonic FLOAT R
288 - 289 Current I2 9th harmonic FLOAT R
290 - 291 Current I3 3rd harmonic FLOAT R
292 - 293 Current I3 5th harmonic FLOAT R
294 - 295 Current I3 7th harmonic FLOAT R
296 - 297 Current I3 9th harmonic FLOAT R
298 - 299 Voltage U1 3rd harmonic FLOAT R
300 - 301 Voltage U1 5th harmonic FLOAT R
302 - 303 Voltage U1 7th harmonic FLOAT R
304 - 305 Voltage U1 9th harmonic FLOAT R
306 - 307 Voltage U2 3rd harmonic FLOAT R
308 - 309 Voltage U2 5th harmonic FLOAT R
310 - 311 Voltage U2 7th harmonic FLOAT R
312 - 313 Voltage U2 9th harmonic FLOAT R
314 - 315 Voltage U3 3rd harmonic FLOAT R
316 - 317 Voltage U3 5th harmonic FLOAT R
318 - 319 Voltage U3 7th harmonic FLOAT R
320 - 321 Voltage U3 9th harmonic FLOAT R
322 - 323 Current I4 A FLOAT R
324 - 325 Voltage U4 U FLOAT R
326 - 327 Current I1 angle ° FLOAT R
328 - 329 Current I2 angle ° FLOAT R
330 - 331 Current I3 angle ° FLOAT R
332 - 333 Current I0 angle ° FLOAT R
334 - 335 Voltage U0 angle ° FLOAT R
336 - 337 Voltage U12 angle ° FLOAT R
338 - 339 Voltage U23 angle ° FLOAT R
340 - 341 Voltage U31 angle ° FLOAT R
342 - 343 Current I4 angle ° FLOAT R
344 - 345 Voltage U4 angle ° FLOAT R
346 - 347 Current positive seq Ip A FLOAT R
348 - 349 Current negative seq In A FLOAT R
350 - 351 Current Ip angle ° FLOAT R
352 - 353 Current In angle ° FLOAT R
354 - 355 Voltage positive seq Up U FLOAT R
356 - 357 Voltage negative seq Un U FLOAT R
358 - 359 Voltage Up angle ° FLOAT R
360 - 361 Voltage Un angle ° FLOAT R
362 - 363 Current I1 2nd harmonic FLOAT R
364 - 365 Current I2 2nd harmonic FLOAT R
366 - 367 Current I3 2nd harmonic FLOAT R
368 - 369 Current I1 channel 2 A FLOAT R
370 - 371 Current I2 channel 2 A FLOAT R
372 - 373 Current I3 channel 2 A FLOAT R
374 - 375 Current I0 channel 2 A FLOAT R
376 - 377 Current I4 channel 2 A FLOAT R
378 - 379 Current I1 channel 2 angle ° FLOAT R
380 - 381 Current I2 channel 2 angle ° FLOAT R
382 - 383 Current I3 channel 2 angle ° FLOAT R
384 - 385 Current I0 channel 2 angle ° FLOAT R
386 - 387 Current I4 channel 2 angle ° FLOAT R
388 - 389 Current Ip channel 2 A FLOAT R
390 - 391 Current In channel 2 A FLOAT R
392 - 393 Current Ip channel 2 angle ° FLOAT R
394 - 395 Current In channel 2 angle ° FLOAT R
396 - 397 Current I1 2nd harmonic ch2 FLOAT R
398 - 399 Current I2 2nd harmonic ch2 FLOAT R
400 - 401 Current I3 2nd harmonic ch2 FLOAT R
402 - 403 THD Current I1 ch2 FLOAT R
404 - 405 THD Current I2 ch2 FLOAT R
406 - 407 THD Current I3 ch2 FLOAT R
408 - 409 Current I1 3rd harmonic ch2 FLOAT R
410 - 411 Current I1 5th harmonic ch2 FLOAT R
412 - 413 Current I1 7th harmonic ch2 FLOAT R
414 - 415 Current I1 9th harmonic ch2 FLOAT R
416 - 417 Current I2 3rd harmonic ch2 FLOAT R
418 - 419 Current I2 5th harmonic ch2 FLOAT R
420 - 421 Current I2 7th harmonic ch2 FLOAT R
422 - 423 Current I2 9th harmonic ch2 FLOAT R
424 - 425 Current I3 3rd harmonic ch2 FLOAT R
426 - 427 Current I3 5th harmonic ch2 FLOAT R
428 - 429 Current I3 7th harmonic ch2 FLOAT R
430 - 431 Current I3 9th harmonic ch2 FLOAT R
#### 6.2 IEC 60870-5-101 operational information IEC 60870-5-101 (IEC101) is a communication protocol designed for telecontrol applications in power systems, enabling communication between a master station and slave devices (e.g., Remote Terminal Units or RTUs). The implementation of IEC101 protocol allows for a data transfer to be initiated only by a master (unbalanced mode). IOMOD Meter via IEC101 protocol transmit various measurement signals in a standardized format. These signals are predefined in the IOMOD and mapped to corresponding Information Object Addresses (IOA). Using IOMod devices along with [WCC Lite](https://wiki.elseta.com/shelves/wcclite-rtu-and-datalogger) allows to send broadcat time synchronization messages to multiple IOMod devices simultaneously. The protocol distinguishes between **Type Identifiers (TI)**, which according to the standard define the format, structure and type of the data being sent. The measurement signals are assigned to two different Type Identifiers 7 and 13. All the measurements are represented in absolute values without any scaling and using standard units. Almost every measurement can be sent using 13 ("measured value, short floating-point number"). The measurements which are sent with TI 13 signals are not marked with timestamps. This is because these signals are not intended for spontaneous transmission upon a change, but rather are to be polled by a controlling (master) station. All energy measurements are assigned to the signals with TI 7, which stands for "bitstring of 32-bit". The necessity in other data formats for the energy measurements comes from the fact that they are saved in 32-bit unsigned integer data type. The usage of integer type instead of float ensures better precision. Table 6.2.1 List of IEC101 measurement signals
**IOA** **Description** **Units** **TI**
0 Current I1 A 13
1 Current I2 A 13
2 Current I3 A 13
3 Current I0 A 13
4 Voltage U12 U 13
5 Voltage U23 U 13
6 Voltage U31 U 13
7 Voltage U1 U 13
8 Voltage U2 U 13
9 Voltage U3 U 13
10 Voltage U0 U 13
11 Voltage U1 angle ° 13
12 Voltage U2 angle ° 13
13 Voltage U3 angle ° 13
14 Apparent power Σ 3 phase VA 13
15 Active power Σ 3 phase W 13
16 Reactive power Σ 3 phase Var 13
17 Power factor Σ 3 phase 13
18 Apparent power S1 VA 13
19 Apparent power S2 VA 13
20 Apparent power S3 VA 13
21 Active power P1 W 13
22 Active power P2 W 13
23 Active power P3 W 13
24 Reactive power Q1 Var 13
25 Reactive power Q2 Var 13
26 Reactive power Q3 Var 13
27 Power factor PF1 13
28 Power factor PF2 13
29 Power factor PF3 13
30 Frequency Hz 13
31 THD Voltage U1 13
32 THD Voltage U2 13
33 THD Voltage U3 13
34 THD Current I1 13
35 THD Current I2 13
36 THD Current I3 13
37 Current I1 3rd harmonic 13
38 Current I1 5th harmonic 13
39 Current I1 7th harmonic 13
40 Current I1 9th harmonic 13
41 Current I2 3rd harmonic 13
42 Current I2 5th harmonic 13
43 Current I2 7th harmonic 13
44 Current I2 9th harmonic 13
45 Current I3 3rd harmonic 13
46 Current I3 5th harmonic 13
47 Current I3 7th harmonic 13
48 Current I3 9th harmonic 13
49 Voltage U1 3rd harmonic 13
50 Voltage U1 5th harmonic 13
51 Voltage U1 7th harmonic 13
52 Voltage U1 9th harmonic 13
53 Voltage U2 3rd harmonic 13
54 Voltage U2 5th harmonic 13
55 Voltage U2 7th harmonic 13
56 Voltage U2 9th harmonic 13
57 Voltage U3 3rd harmonic 13
58 Voltage U3 5th harmonic 13
59 Voltage U3 7th harmonic 13
60 Voltage U3 9th harmonic 13
61 Current I4 A 13
62 Voltage U4 U 13
63 Current I1 angle ° 13
64 Current I2 angle ° 13
65 Current I3 angle ° 13
66 Current I0 angle ° 13
67 Voltage U0 angle ° 13
68 Voltage U12 angle ° 13
69 Voltage U23 angle ° 13
70 Voltage U31 angle ° 13
71 Current I4 angle ° 13
72 Voltage U4 angle ° 13
73 Current positive seq Ip A 13
74 Current negative seq In A 13
75 Current Ip angle ° 13
76 Current In angle ° 13
77 Voltage positive seq Up U 13
78 Voltage negative seq Un U 13
79 Voltage Up angle ° 13
80 Voltage Un angle ° 13
81 Current I1 2nd harmonic 13
82 Current I2 2nd harmonic 13
83 Current I3 2nd harmonic 13
84 Current I1 channel 2 A 13
85 Current I2 channel 2 A 13
86 Current I3 channel 2 A 13
87 Current I0 channel 2 A 13
88 Current I4 channel 2 A 13
89 Current I1 channel 2 angle ° 13
90 Current I2 channel 2 angle ° 13
91 Current I3 channel 2 angle ° 13
92 Current I0 channel 2 angle ° 13
93 Current I4 channel 2 angle ° 13
94 Current Ip channel 2 A 13
95 Current In channel 2 A 13
96 Current Ip channel 2 angle ° 13
97 Current In channel 2 angle ° 13
98 Current I1 2nd harmonic ch2 13
99 Current I2 2nd harmonic ch2 13
100 Current I3 2nd harmonic ch2 13
101 THD Current I1 ch2 13
102 THD Current I2 ch2 13
103 THD Current I3 ch2 13
104 Current I1 3rd harmonic ch2 13
105 Current I1 5th harmonic ch2 13
106 Current I1 7th harmonic ch2 13
107 Current I1 9th harmonic ch2 13
108 Current I2 3rd harmonic ch2 13
109 Current I2 5th harmonic ch2 13
110 Current I2 7th harmonic ch2 13
111 Current I2 9th harmonic ch2 13
112 Current I3 3rd harmonic ch2 13
113 Current I3 5th harmonic ch2 13
114 Current I3 7th harmonic ch2 13
115 Current I3 9th harmonic ch2 13
400 Active import energy kWh 7
401 Active export energy kWh 7
402 Reactive import energy kVArh 7
403 Reactive export energy kVArh 7
#### 6.3 IEC 60870-5-103 operational information When the IEC-60870-5-103 protocol is selected IOMOD Meter uses a standard communication scheme. Initiation, control messages, and queries are initiated by a master (controlling station), while the IOMOD device (controlled station) only answers requests and sends values. The first message sent by the master should be RESET CU to restart communication. When an *acknowledge* (ACK) packet is sent from a slave device, a master may proceed with acquiring *General Interrogation* and sending *Time synchronization* packets. When this initialization is complete, the master should poll the IOMod Meter with Class 1 and Class 2 requests. Class 2 is used when the master polls for cyclic data. The controlled device responds when spontaneous data exists and the master then sends a request for Class 1. The controlled station responds with a time-tagged message. As IOMod Meter does not have any digital inputs, only analog ones, therefore the general interrogation returns nothing. Values of measurements are returned cyclically as a response to Class 2 data requests. Specific settings for the IEC 60870-5-103 protocol: 1. Measurand set selection. A user can select which predefined measurand set will be transmitted to the host system. Available measurand sets are presented in table 6.3.1. 2. Scale factor. The communication protocol IEC 60870-5-103 only lets 13-bit signed values in the range of -1...+1. When an IEC 60870-5-103 measurand, for example, phase voltage, is scaled as 2.4, it means that the measurand value 1 corresponds to 2.4 multiplied by Un, the measurand value 0.5 corresponds to 1.2 multiplied by In, and so on. If the measurand value, in this case, exceeds 2.4 multiplied by Un, the IEC 60870-5-103 object value saturates at its maximum value and an overflow flag is set in the IEC 60870-5-103 object transmission. 3. Device function type. By default, IOMOD has IEC 60870-5-103 Function Type set to 253. If this Function type for some reason is not suitable – a user can define any other type Table 6.3.1. Data sets for 3I3U connection mode
**Set Nr.** **TYPE** **FUN\*** **INF** **Qty of data** **Information elements (measurands)**
1 9 253 148 9 I1, I2, I3, U1, U2, U3, P, Q, f
2 9 253 149 23 I1, I2, I3, I4, U1, U2, U3, U4, P1, P2, P3, Q1, Q2, Q3, S1, S2, S3, PF1, PF2, PF3, U12(angle), U23(angle), U13(angle)
3 9 253 150 60 I1, I2, I3, IN, U1, U2, U3, UN, P1, P2, P3, Q1, Q2, Q3, S1, S2, S3, PF1, PF2, PF3, U12, U23, U13, f, THDU1, THDU2, THDU3, THDI1, THDI2, THDI3, I1(h2), I1(h3), I1(h5), I1(h7), I1(h9), I2(h2), I2(h3), I2(h5), I2(h7), I2(h9), I3(h2), I3(h3), I3(h5), I3(h7), I3(h9), U1(h2), U1(h3), U1(h5), U1(h7), U1(h9), U2(h2), U2(h3), U2(h5), U2(h7), U2(h9), U3(h2), U3(h3), U3(h5), U3(h7), U3(h9)
4 9 253 151 54 I1, I2, I3, IN, U12, U23, U13, UN, S, P, Q, PF, THDU1, THDU2, THDU3, THDI1, THDI2, THDI3, I1(h3), I1(h5), I1(h7), I1(h9), I2(h3), I2(h5), I2(h7), I2(h9), I3(h3), I3(h5), I3(h7), I3(h9), U1(h3), U1(h5), U1(h7), U1(h9), U2(h3), U2(h5), U2(h7), U2(h9), U3(h3), U3(h5), U3(h7), U3(h9), P1, P2, P3, Q1, Q2, Q3, U1(angle), U2(angle), U3(angle), U1, U2, U3
6.3.2 Data sets for 3I3I connection mode
**Set Nr.** **TYPE** **FUN\*** **INF** **Qty of data** **Information elements (measurands)**
1 9 253 148 7 I1(ch1), I2(ch1), I3(ch1), I1(ch2), I2(ch2), I3(ch2), f
2 9 253 149 8 I1(ch1), I2(ch1), I3(ch1), I4(ch1), I1(ch2), I2(ch2), I3(ch2), I4(ch2)
3 9 253 150 45 I1(ch1), I2(ch1), I3(ch1), I0(ch1), I1(ch2), I2(ch2), I3(ch2), I0(ch2), f, THDI1(ch1), THDI2(ch1), THDI3(ch1), I1(h3, ch1), I1(h5, ch1), I1(h7, ch1), I1(h9, ch1), I2(h3, ch1), I2(h5, ch1), I2(h7, ch1), I2(h9, ch1), I3(h3, ch1), I3(h5, ch1), I3(h7, ch1), I3(h9, ch1), THDI1(ch2), THDI2(ch2), THDI3(ch2), I1(h3, ch2), I1(h5, ch2), I1(h7, ch2), I1(h9, ch2), I2(h3, ch2), I2(h5, ch2), I2(h7, ch2), I2(h9, ch2), I3(h3, ch2), I3(h5, ch2), I3(h7, ch2), I3(h9, ch2)
The certain set of measurements can be configured in IOMod Utility General settings (see Table 5.1.1, Fig 6.3.1). [![image-1729167116205.png](https://wiki.elseta.com/uploads/images/gallery/2024-10/scaled-1680-/image-1729167116205.png)](https://wiki.elseta.com/uploads/images/gallery/2024-10/image-1729167116205.png) Fig. 6.3.1. IOMod Utility General settings IEC 60870-5-103 protocol parameters Type 9 signals allocate only 13 bits for measurement values, which is not enough for float values to be transferred. For that reason, all measurement data are being scaled. However, not all values are scaled the same. All currents, voltages and power measurements are scaled using the same algorithm. The range of the maximum and the minimum measurement values, which can be transferred with IEC103 protocol is calculated by multiplying the nominal value by scale factor: *MMV = SF* ⋅ *NV* (6.3.1) - MMV – maximum measurement value; - NV – nominal value; - SF – scale factor; The scale factor of most measurements can be selected in IOMod Utility General settings (Table 5.1.1, Fig. 6.3.1). The maximum measurement value (MMV) is only the upper limit of the allowed range. The full allowed range goes from -MMV up to +MMV. Since the first bit is used to denote the sign, the maximum absolute value, which can be sent via IEC 60870-5-103 communication protocol is 212 = 4096. The MMV is mapped to this value, so that if the measured value is equal to the MMV, 4096 is going to be sent to a controlling station via IEC103 protocol. If a measurement value exceeds MMV, then the overflow is going to be indicated by the signal and 4096 is going to be sent. If a measured value is inside of the allowed range, then the scaled value, which is going to be sent by means of IEC103 signal, is calculated by multiplying it by 4096 and dividing it by the maximum measurement value: *SV = MV ⋅ 4096MMV, where -MMV ≤ MV ≤ +MMV* (6.3.2) - SV – scaled value, which is going to be sent by means of IEC103 protocol; - MV – measured value, which must be in the allowed range; - MMV – maximum measurement value; In the special case, where measured value is equal to the nominal value the scaled value formula can be simplified as: *SV = NV ⋅ 4096SF ⋅ NV = 4096SF* (6.3.3) The scaled values of other measurands are calculated by using different scaling techniques. The scaled frequency is calculated by multiplying the measured frequency by 50. All angle measurements are scaled by a factor of 10.