Modbus (modb1) data stream definitions

The following table provides data stream definitions for the Modbus protocol.

Some data stream information pushed to Remote Manager includes the Modbus device address identified during device detection. For examples, see About data streams.

Short name Long name Description
aem Alarm enable mask

Modbus alarm enabled or disabled:

0 — Modbus alarm disabled

1 — Modbus alarm enabled
baud Baud rate

The baud rate. Value can be 600 - 230400.

 
dbt Data bits

The number of data bits that can be sent in a packet:

  • 7
  • 8
ena Modbus protocol enable

Modbus protocol enabled or disabled:

0 — Modbus protocol disabled

1 — Modbus protocol enabled
err Error response status value

Error values:

1 - Illegal function

2 - Illegal data address

3 - Illegal data value

4 - Device failure

128 - Timeout
mode Modbus serial transmission mode

Specifies the Modbus serial transmission mode:

  • rtu
  • ascii
par Parity

The check bit for detecting an error in transmission:

  • none
  • odd
  • even
saddr<1-4> Modbus station addresses The station address number that is configured for the Modbus sensor device.
sbt Stop bit

The bit that marks the end of a unit transition.

  • 1
  • 2
val Variable that returns a value

Coils and discrete inputs will be 0 or 1.

Input and holding registers will be 16-bit unsigned integer values, or signed floating point values, depending on configuration.
vars<1-4> Corresponding Modbus variable list Comma-separated list of variable addresses.

Data streams for Modbus protocol

Item Name Description
1 Connect Tank device ID Identifies the device.
2 Group

Identifies the device-specific function or sensor for the data stream. For example, modb1 corresponds to the sensor for a device with Modbus protocol enabled.
3 Modbus station address Identifies the station address that is being monitored.
4 Modbus variable address Identifies the variable address that is being monitored at the specified station address.
5 Short name

Identifies the specific data point. In this example, val is the value that is returned.