[volttron-dev] Write-Only Modbus Registers in Modbus-TK

["Thompson, Joe" <jthompson@xxxxxxxx>]

Hello Volttron Team, 

 

Background:

I am using Volttron 8.1.3 on a Raspberry Pi to coordinate the operation / testing of 2 devices over Modbus:

1. An energy storage system with a BMS that Volttron’s platform.driver communicates with over modbus
2. An inverter that also communicates with Volttron’s platform.driver via modbus

 

I have a few registers on the BMS that are write-only which are used to close contactors within the system. Manually writing to these registers works fine, but if I try manually reading from them I get a “reply timeout” error:

 

Im wondering if there’s a way to configure a write-only register in Volttron. As I currently understand, I can configure points as either read or read / write in the platform driver and all of these registers will be read by the platform driver in each scraping interval. Is there a way to configure a group of points such that they are never read but are available to be written to by the platform driver? Im concerned that adding these points to my existing list of readable points will slow down the scraping process due to these timeouts.

 

Thanks!

 

Joe Thompson

Technical Leader

Electric Power Research Institute

Energy Storage and Distributed Generation

(912) 663-3407

 

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