Too long register response time with Total Active Energy Import iEM3000

[Jak_Saut93]

Hello,

All registers except the energy consumption register are read correctly. Every 10 seconds I have a reading in the BMS system (this is how it was set in the controller). Unfortunately, register 45100 is read after 24 hours or longer.

I directly checked the reading through the Moxa U-port in the modscan32 program, the reading of this register was correct. Each change in the value of this register was read, I did the same using our driver. We can set the serial port through the controller and then we can read Modbus registers using other programs, for example modscan32. Similarly, we had a correct reading.

Register 45100 is read by our system as register 45098, similarly we need to shift the remaining registers down by 2. Everything is read at a given interval, unfortunately we still have problems with total consumption. I would like to ask for advice on how we can deal with this problem.

Below I am sending screenshots of the Modbus configuration in our system:

We read data by main channel 9600 RTU/8/None/1

Regards

Jakub

 

[Ramasamy_N]

Hi @Jak_Saut93 

Can you connect with tech support team with the screenshots? I am unbale view this attachment. 

[Robert_Lee · Accepted solution]

Register 45100 for most PowerLogic devices is stored as a IEEE-754 single precision FLOAT32 register value.  This means any Modbus request would likely need to send a Read Holding Register request asking for 2 registers and interpret the response accordingly.

I have no idea why you would reduce the address by 2 unless that is some strange requirement in the BMS software.  When using most standard Modbus software like MODSCAN32, addressed entered via the ui are expressed in PDU+1 addressing (as is Schneider documentation).

This means if we state the register is located at address 45100 the PDU register address (i.e. the one sent to the device is that minus 1 so 45099 is sent to the device).  Most applications like MODSCAN32 hide this fact and expect you to enter the published PDU+1 addressing.