Modbus Sensor Bridge

How to install your Modbus Sensor Bridge

Julien Stamatakis avatar
Written by Julien Stamatakis
Updated over a week ago

Senseware’s Modbus sensor bridge has two sets of identical inputs connected on the same bus. This allows for simple daisy-chaining with other Modbus RTU devices on the network.


The three connectors are labeled +, -, and X, as shown in the figure below. Connect ports + and - on the sensor bridge with their counterparts on the Modbus meter. These ports might be labeled A and B on the Modbus meter. Traditionally, A refers to negative polarity (-) and B refers to positive polarity (+). However, it is possible that a meter’s A port will refer to positive polarity (+) and its B port will refer to negative polarity (-). If you are having trouble communicating with a Modbus meter, try switching the cables. If a cable shield is present, connect it to the X port on the sensor bridge.


Wires only need to be connected to one set of wire terminals on the Modbus sensor bridge. The second set of wire terminals is provided for convenience and ease of installation when the Modbus sensor bridge is not located at an endpoint of the network. In most cases, only one Modbus sensor bridge is all that is needed for a given Modbus network. Once the Modbus sensor bridge is properly wired, connect it to an available port on the node and power the node.

For web configuration information, click here.

Technical Specifications:

Power: 3.3V DC from node or gateway via micro-USB connector
Inputs: 2 x 3 Wire RS-485
Bridge Output: Up to 1000 single read operations or 500 range read operations (16/32 bits). Maximum 150 registers in a single range read operation.
Size (inches): 2.1 x 2.1 x 0.4
Weight (ounces): 0.8

Note: If you have a Modbus bridge that has three connectors on each port as depicted on the image below, the number of registers that can be read is lower than the number listed above.

Did this answer your question?