# 14.5 IEC 60870-5-104 Master IEC 60870-5-104 protocol (in short IEC 104) is a part of IEC Telecontrol Equipment and Systems Standard IEC 60870-5 that provides a communication profile for sending basic telecontrol messages between two systems in electrical engineering and power system automation. Telecontrol means transmitting supervisory data and data acquisition requests for controlling power transmission grids. IEC 104 provides network access to IEC 60870-5-101 (in short IEC 101) using standard transport profiles. In simple terms, it delivers IEC 101 messages as application data (L7) over TCP, usually port 2404. IEC 104 enables the communication between the control station and a substation via a standard TCP/IP network. The communication is based on the client-server model.

To set up TLS connection for both IEC104 Master and Slave, refer to sections Excel configuration and Certificates. All keys and certificates should be provided in the PEM format.

If no configuration is set up, IEC104 Master and Slave services are not started.

#### Configuring IEC 104 Master datapoints To use IEC 60870-5-104 Master in WCC Lite, it has to be configured via an Excel configuration. This configuration contains two Excel sheets where parameters have to be filled in Devices and Signals. ##### IEC 60870-5-104 Master parameters for *Devices* tab

Parameter	Type	Description	**Required	Default value (when not specified)	Range
Parameter	Type	Description	**Required	Default value (when not specified)	Min	Max
name	string	User-friendly name for a device	Yes
description	string	Description of a device	No
device\_alias	string	Alphanumeric string to identify a device	Yes
enable	boolean	Enabling/disabling of a device	No	1	0	1
protocol	string	Protocol to be used	Yes		IEC 60870-5-104 master
asdu\_address	integer	Application Service Data Unit address	Yes		0	65535
asdu\_size	integer	Common address size in bytes	No	2	1	2
time\_sync\_interval\_sec	integer	Time frame between Time Synchronization requests in seconds	Yes	60
gi\_interval\_sec	integer	Time frame between General Interrogation requests in seconds. If 0 requests are disabled	Yes	300
port	integer	TCP port	Yes		0	65535
ioa\_size	integer	Information object address (IOA) size in bytes	No	3	1	3
swt	integer	Send window (k)	Yes
rwt	integer	Receive window (w)	Yes
cot\_size	integer	Cause of transmission (COT) size in bytes	No	2	1	3
ip	string	Host IP address (ipv4)	Yes
t1\*	integer	Acknowledge timeout t1 (sec)	Yes	15	1	255
t2\*	integer	Connection ACKRSN clock t2 (sec)	Yes	10	1	254
t3\*	integer	Connection TESTFR clock t3 (sec)	Yes	20	1	172800
originator	integer	Provides a means for a controlling station to explicitly identify itself	No	0	0	255

\* - t1, t2 and t3 parameters must meet the inequality: t2<t1<t3. ##### IEC 60870-5-104 Master parameters for *Signals*

Parameter	Type	Description	**Required	Default value (when not specified)	Range
Parameter	Type	Description	**Required	Default value (when not specified)	Min	Max
signal\_name	string	User-friendly signal name	Yes
device\_alias	string	Alphanumeric string to identify a device	Yes
signal\_alias	string	Unique alphanumeric name of the signal to be Yes used	Yes
source\_device\_alias	string	device\_alias of a source device	For commands
source\_signal\_alias	string	signal\_alias of a source signal	For commands
enable	boolean	Enabling/disabling of an individual signal	No	1	0	1
log	integer	Allow signal to be logged. If log is 0 signal will not be logged. If log is more than 0 signal will be logged	No	0
gi	boolean	Including/excluding (1 or 0) signal from General Interrogation	No	0	0	1
common\_address	integer	Address of a destination device	Yes
function	integer	Function number	No	0
info\_address	integer	Information object address	Yes
data\_type	integer	ASDU type identifier	Yes		1, 3, 5, 9, 11, 13, 21, 30, 31, 32, 34, 35, 36, 45, 46, 47, 48, 49, 50, 58, 59, 60, 61, 62, 63
select\_ms	integer	Time limit in milliseconds for command execution. Command select has to be performed before execution if this parameter is specified. Direct command execution can be performed only if this field is left empty or set to zero.	No	0

##### Device status signals

IEC 60870-5-104 has an additional signal which can be configured to show communication status. It is used to indicate if the slave device has disconnected from master (WCC Lite). To configure such signal for IEC 60870-5-104 protocol, job\_todo and tag\_job\_todo fields with string values are required. For IEC 60870-5-104 master required parameters for status signal will be: **signal\_name** **device\_alias, signal\_alias, common\_address, info\_address, data\_type, job\_todo** and **tag\_job\_todo**. Job\_todo value must be *device\_status* and for tag\_job\_todo there are 4 variations: communication\_status, device\_running, device\_error, uknown\_error. Each signal has 4 possible values and are based on the same logic. If signal returns value of 0, it means unknown error has appeared, 1 – device or protocol connection is on and working properly, 2 – device is off or protocol is disconnected, 3 – error or service is down. ### Debugging an IEC 60870-5-104 Master application If the configuration for IEC 60870-5-104 devices is set up, the handler for the protocol will start automatically. If a configuration is missing parameters or contains errors, the protocol will not start. It is done intentionally to decrease unnecessary memory usage. If IEC 60870-5-104 does not work properly (e.g. no communication between devices, data is corrupted, etc.), a user can launch a debug session from the command-line interface and find out why the link is not functioning properly or use WCC Utility to do that. To launch a debugging session, a user should stop the *iec104-master* process and run the *iec104-master* command with respective flags. - Step 1: Service must be stopped by entering the following command into the WCC Lite: **/etc/init.d/iec104-master stop** - Step 2: After service is stopped it must be started with the preferred configuration file (JSON files found in /etc/ folder) and a debug level 7: **iec104-master -c /etc/iec104-master/iec104-master.json -d7** - Step 3: Once the problem is diagnosed normal operations can be resumed with the following command: **/etc/init.d/iec104-master start** ##### IEC 60870-5-104 command-line debugging options ``` -h [ –help ] Display help information -V [ –version ] Show version -d Set debugging level -c [ –config ] Config path -r [ –raw ] Show raw telegram data -f [ –frame ] Show frame data

-e [ –redis ] Show redis message -R [ –readyfile ] Ready notification file ```