Configuring a Johnson Controls BMS to truncate some least significant digits in received value transmitted by our energy meter

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Hello All,

Greetings from Power Monitoring team - Bangalore, India!

There's a customer in Malaysia who is using our PM1200 Energy meter with a Johnson Controls Building Management System (I have asked for the exact tool that they are using, version info, etc.). For zero current and voltage, our meter reads zero on its display but transmits a very small non-zero value (of the order of 10^-18) through its RS485 communication. Protocol used is MODBUS, data type is FLOAT32. This miniscule non-zero value is present because of some limitation in the calculation algorithm used in the meter.

The customer wants to read an exact zero through communication in the absence of current and voltage. We have asked him to configure his BMS to truncate the last few (least significant) digits from the received value. Doing so will give an exact zero as desired. But he seems to be having trouble following this.

I am not familiar with the Johnson Controls BMS, but I believe there must be some way to configure the tool to truncate least significant digits from a received value. Is there someone who is aware of the Johnson Controls BMS tool and can help me understand / guide me how to configure it so that it will truncate some least significant digits in received value (transmitted by our energy meter)?

Thanks & Regards,

Sutanu.