Modbus string points

Modbus string points can function as either input (read) only or input/output (read/write) points. This is set by checking the "Write" checkbox in the Telemetry Server dashboard.

Modbus string point syntax

Telem_Server_<ScopeName>:%<OutstationFullName>;<PointType>;<PointAddress>;<Length>;<StringType>{;[<PointName>]}

• PointType: STR

• PointAddress: a 5 or 6 digit decimal number, depending on the Point Address Range setting of the outstation. The default setting is 5 digits. The range of valid addresses vary by point type and maps to the "Address" field in the Telemetry Server dashboard.

• Length: a decimal number from 1 to 247 that sets the maximum string length and maps to Requested String's Length in the Telemetry Server dashboard.

• String type: one of the values listed in the following table, for example, ASCIILOW. This value maps to the "StringType" field in the Telemetry Server database.

  String Type	Definition
  ASCIILOW	Single byte ASCII, first character in low byte
  ASCIIHIGH	Single byte ASCII, first character in high byte
  UNICODE	Two byte Unicode

• PointName (optional): a descriptive name for the point, for example, LiftStationPump_01. If specified, the PointName must be enclosed in brackets.

  • If PointName is not specified, the point is assigned a default name that uses point type and point address, in the format PointType_PointAddress, for example, STR_30002.

  • If you want to create the new point in a different group than the Outstation group, include the group name: GroupName.PointName.

String reference example

Without optional PointName:

Telem_Server_Node-12:%Group.Modbus_RTU;STR;30002;20;ASCIILOW

References the 20-character ASCII string point mapped to a block of input registers starting at 30002, which is given the name STR_30002

With optional PointName:

Telem_Server_Node-12:%Group.Modbus_RTU;STR;30002;20;ASCIILOW;[Tag_Name]

References the 20-character ASCII string point mapped to a block of input registers starting at 30002, which is named Tag_Name