Supported protocols

For all supported field protocols, device communication can be examined through the Device watch and Debugger tools in the Client.

MODBUS

MODBUS is a master-slave communication protocol. Telecontrol SCADA supports MODBUS over RS-485, RS-422, RS-232, and Ethernet TCP/IP, covering MODBUS RTU, ASCII, and TCP deployments.

The Server exchanges telemetry and control values through standard MODBUS function codes and maps them to SCADA objects.

See also the engineering reference for MODBUS devices.

IEC 60870-5

IEC 60870-5 directions define data channels such as a network endpoint or serial port. One direction can serve multiple devices.

Supported application-layer ASDU types include:

ASDU label Type ID Description
M_SP_NA_1 1 Single-point information
M_SP_TA_1 2 Single-point with timestamp
M_DP_NA_1 3 Double-point information
M_BO_NA_1 7 32-bit bitstring
M_ME_NA_1 9 Normalized measured value
M_ME_NB_1 11 Scaled measured value
M_ME_TB_1 12 Scaled measured value with timestamp
M_ME_NC_1 13 Short floating-point measured value
M_IT_NA_1 15 Integrated total
M_SP_TB_1 30 Single-point with CP56Time2a
M_DP_TB_1 31 Double-point with CP56Time2a
M_ME_TD_1 34 Normalized value with CP56Time2a
M_ME_TE_1 35 Scaled value with CP56Time2a
M_ME_TF_1 36 Float value with CP56Time2a
M_IT_TB_1 37 Integrated total with CP56Time2a
C_SC_NA_1 45 Single command
M_EI_NA_1 70 End of initialization
C_IC_NA_1 100 General interrogation
C_CI_NA_1 101 Counter interrogation
C_CS_NA_1 103 Time synchronization
C_RP_NA_1 105 Reset process
P_ME_NA_1 110 Parameter write, normalized
P_ME_NB_1 111 Parameter write, scaled
P_ME_NC_1 112 Parameter write, float

For control operations, Telecontrol SCADA uses:

  • C_SC_NA_1 for discrete control objects
  • P_ME_NC_1 for measured-value control objects

The ASDU type can be overridden in the output field with the format type:address, where type is one of:

  • BOOL to use C_SC_NA_1
  • INT16 to use P_ME_NB_1
  • FLOAT to use P_ME_NC_1

This override is useful when a measured object must be controlled with C_SC_NA_1 instead of the default measured-value command ASDU.

When UDP server mode is used, multiple remote devices can share one direction. Devices are identified by the remote IP address and port, so separate listening ports are not required for each one. UDP mode also supports devices that send datagrams built from multiple IEC messages.

See also the engineering reference for IEC 60870-5 devices.

IEC 61850

IEC 61850 support provides transparent access to the device information model. Data acquisition is performed through subscriptions to RCB/BRCB report blocks transported over MMS.

Before data collection can begin, the required report blocks must exist on the IEC 61850 device. After a connection is established, the Server configures those report blocks for spontaneous event transmission.

Object binding uses MMS addresses in the format:

LogicalDevice/LogicalNode$FC$DataObject

Typical functional constraints are:

  • FC=ST for discrete-state bindings
  • FC=MX for measured-value bindings
  • FC=CO for control commands

Two-stage control commands are supported.

Only UTC timestamps are supported. If the device uses a different time zone, timestamp handling may become problematic.

The operator can also initiate a full interrogation of the device.

Translation status

This English page is now a functional protocol reference. The Russian page still contains fuller wording and a few extra implementation notes.