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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
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 60870­-5-104 slave
asdu_size integer Common address size in bytes No 2 1 2
time_sync boolean Enable/disable (1 or 0) time synchronization Yes


port integer TCP port No 2404 0 65535
ioa_size integer Information object address (IOA) size in bytes No 3 1 3
swt integer Send window (SWT) No 12

rwt integer Receive window (RWT) No 8

cot_size integer Cause of transmission (COT) size in bytes No 2 1 3
host string Space-separated remote host IP addresses (ipv4) Yes


bind_address string Bind to local IP address (ipv4) No 0.0.0.0

t1

integer Acknowledge timeout t1 (sec) Yes 15 1 255
t2 integer

Connection ACKRSN clock t2 (sec),

t2 should be less than t1

Yes 10 1 254
t3 integer Connection TESTFR clock t3 (sec) Yes 20 1 172800
message_size boolean The maximum length of a message Yes 253 0 255
cache_size integer Amount of data to be cached Yes 100 0 1000
tls boolean Enable/disable the use of TLS No 0 0 1
tls_local_certificate string Local certificate for TLS connection Yes (for TLS)


tls_peer_certificate string Certificate authority file for TLS connection No


tls_private_key string A file consisting of the private key for TLS connection No


command_timeout_ms integer Time to execute a command before responding negatively. No 30000 0
command_age_ms integer The amount of time shift allowed for the command to still be executed. No 0 0
IEC 60870­-5­-104 Slave 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 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 0 1
gi boolean Including/excluding (1 or 0) signal from General Interrogation No 0 0 1
common_address integer Address of a destination device Yes


info_address integer Information object address Yes


data_type integer ASDU type id. 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 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