14.2 IEC 60870-5-101 Master

The IEC 60870-­5-­101 protocol is a companion standard for power system monitoring, control associated communications for telecontrol, teleprotection and associated telecommunications for electric power systems. Standard IEC 60870-­5­-101 was prepared by IEC technical committee 57 (Power system control and associated communications).

Standard IEC 60870-­5-­101 defines an Application Service Data Unit (ASDU Figure below). In ASDU there is an ASDU identifier (with the type of ASDU in it) and information objects.image-1638258623652.png

IEC 60870­-5-­101 ASDU structure

Common Address of ASDU Defines the stations' address and can be configured in Devices asdu_address field for source and Signals common_address field for the destination.

Information Object Address Used as destination object address in the control direction and as source object address in monitor direction can be configured in Signals info_address field.

Standard IEC 60870­-5­-101 transmission frames are separated into 3 different types: frame with variable length, frame with fixed length, and single control characters

image-1638259001158.png

IEC 60870­-5-­101 ASDU structure

Control field provides information about the message direction, type of service, and checksum.

Address field specifies the link address which points to the message's destination. WCC Lite supports IEC 60870-­5-­101 Master protocol over a serial link (according to EIA RS­485). Its full functionality list can be found in an IEC 60870­-5-­101 PID Interoperability List which can be downloaded separately from this user manual.

Configuring datapoints (master)

To use IEC 60870-­5-­101 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 60870-­5-­101 master parameters for Devices tab
Parameter

Type

Description

Required

Default value

(when not specified)

Range

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 60870­-5-101 master
device

string

Communication port

Yes


PORT1

PORT2

baudrate integer

Communication speed (bauds/s)

No

9600

300, 600, 1200, 2400, 4800, 9600, 19200, 38400, 57600, 115200

databits integer

Data bit count for communication

No

8

6

9

stopbits integer

Stop bit count for communication

No

1

1

2

parity

string

Communication parity option

No

none

none, even, odd


flowcontrol

string

Number of requests, before link is considered lost (device status signals are changed) and reconnect attempt will be issued

No

none

none


link_address integer Destination address when in transmit and source address when broadcasting Yes
0 65535
link_size integer Link address size in bytes No 1 1 2
asdu_address integer Application Service Data Unit address Yes
0 65535
asdu_size integer Common address size in bytes No 1 1 2
ioa_size integer Information object address (IOA) size in bytes No 2 1 3
cot_size integer Cause of transmission (COT) size in bytes No 1 1 2
time_sync_interval_sec integer Defines how often (in seconds) slave will
request time synchronization. If greater than 0 ­slave will request synchronizations, will reset the timer if the master did it earlier. If 0 slave won’t request timesyncs, but will allow them. If ­1 ­ timesyncs are not supported ­ requests will be dropped.
No 60

gi_interval_sec integer Time frame between General Interrogation requests in seconds, if 0 requests are disabled No 300



scan_rate_ms integer

Polling interval in milliseconds. Time frame between two telegrams from master

Yes 100

timeout_ms integer

Response timeout in milliseconds

Yes

1000



retry_count integer

Number of retries of failed requests before announcing that device is in Error state

Yes 1

IEC 60870­-5-­101 master parameters for Signals tab
Parameter

Type

Description

Required

Default value

(when not specified)

Range

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 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 1

info_address integer Information object address Yes


data_type integer ASDU type identifier  Yes
1, 2, 3, 4, 5, 6, 9, 10, 11, 12, 13, 14, 30, 31, 32, 34, 35, 36, 45, 46, 47, 48, 49, 50
Device status signals

IEC 60870-­5-­101 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 60870-­5-­101 protocol, job_todo and tag_job_todo fields with string values are required. For IEC 60870-­5-­101 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 a IEC 60870-­5­-101 Master application

If configuration for IEC 60870-­5-­101 devices is set up, handler for protocol will start automatically. If the configuration is missing parameters or contains errors, protocol will not start. It is done intentionally decrease unnecessary memory usage.

If IEC 60870-­5-­101 does not work properly (e.g. no communication between devices, data is corrupted, etc.), a user can launch a debug session from command line interface and find out why link is not functioning properly. To launch a debugging session, a user should stop iec101­-master process and run iec101-­master command with respective flags as shown in the table below.

Procedure for IEC 60870-­5-­101 master service debugging:

IEC 60870-­5­-101 command line debugging options
-h [ –help ] Display help information 
-V [ –version ] Show version
-d<debug level> Set debugging level 
-c [ –config ] Config path
-r [ –raw ] Show raw telegram data
-f [ –frame ] Show frame data
-R [ –readyfile ] Ready notification file


Revision #1
Created 11 January 2024 09:21:49 by Gabriele
Updated 11 January 2024 09:38:19 by Gabriele