PM5560 and iem3155 restoring power to meter - data time delay

[Rolla]

We have an issue restoring the data from an iem3155, via Modbus serial connection to a PM5560. When the bus plug breaker is flipped off, we receive the data loss within seconds, but when the bus plug breaker is flipped back on, there is a 10 minute delay before seeing the bus plug back on via the BMS. Is this to do with polling? We have (15) IEM3155 daisy chained to (1) PM5560, and apart of commissioning they are flipping multiple breakers along this daisy chain to test the BMS. 

[Charles_Murison · Accepted solution]

Hello @Rolla ,

There are a number of different factors that could be coming into play. One for example could be inside the BMS system itself. Many programs have a way of flagging a device as offline, when this happens the software will not request data from the device as often. This can be used to preserve serial line utilization. If a device is known to timeout every time you ask for information, no other device on the serial line can be polled until the timeout has expired. This can result in a serial line spending a large percentage of the time just waiting for a timeout rather than communicating with the other devices on the serial loop. 

Programs like PME, the number of tried before marking a device offline can be configured as well as how long to wait before trying to talk to the device again. Perhaps this BMS system has similar configuration or settings.

Regards,

Charles