Issue
When using the Modbus RTU X Driver to communicate to multiple Socomec Diris A20 electric meters it has been found only 2 or 3 devices can be networked together, even using a b-Link to boost the signal does not resolve the issue.
Product Line
Andover Continuum
Environment
- Modbus RTU X Driver on bCX1 or Netcontroller II
- B-Link repeaters
Cause
The Socomec Diris A20 meters require a minimum of 4V RS-485 signal to communicate reliably, but the EIA RS-485 standard only calls for a +/- 1.5 volts signal and the Receiver Input sensitivity should be +/- 200mV.
When using a bCX1 with the X Driver on Comm1 you will require a b-Link to provide the RS-232 to RS-485 conversion, although the B-Link fully conforms to the EIA RS-485 standard it does not have the drive levels required by the Socomec products.
Resolution
To resolve the non standard electrical requirement of the Socomec Diris meters use a Socomec RS-422/ RS-485 Repeater this will output the required electrical levels required by the Diris meters, the Socomec part reference is 48990120. Please refer to SOCOMEC Communication accessories or RS-422/485 Repeater Operating Instructions
If a B-Link is to be used each RS-485 output that is used will require a separate Socomec repeater.
