14.6 IEC 60870-5-104 Slave

IEC 60870-5-104 Slave is designed not to lose data acquired from Master protocols. The data that arrives from Master protocols is stored in the cache. This data is checked every second to manage further data sending. The data that leaves IEC 60870-5-104 Slave has output caches. They’re built to provide switching between multiple sessions (redundant SCADA). If a new connection arrives, the old one is dropped, but data, that is stored in a cache, not sent and not confirmed by SCADA is transferred to the new connection.

Configuring IEC 104 Slave datapoints

To use IEC 60870-­5­-104 Slave 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 Slave parameters for Devices tab

IEC 60870­-5­-104 Slave parameters for Signals tab

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 master device has disconnected from slave (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 slave 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 Slave 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-slave process and run the iec104-slave command with respective flags.

• Step 1: Service must be stopped by entering the following command into the WCC Lite:
  /etc/init.d/iec104-­slave 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-­slave­-c /etc/iec104-slave/0_0_0_0_502.json -­d7;
  (0_0_0_0 - bind_address, 502 - port)
• Step 3: Once the problem is diagnosed normal operations can be resumed with the following command: /etc/init.d/iec107-­slave start

IEC 60870-­5­-104 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
­-e [ –redis ] Show redis message
-R [ –readyfile ] Ready notification file