Configuring a Johnson Controls BMS to truncate some least significant digits in received value transmitted by our energy meter
Metering & Power Quality
Schneider Electric support forum about Power Meters (ION, PowerTag, PowerLogic) and Power Quality from design, implementation to troubleshooting and more.
Send a co-worker an invite to the portal.Just enter their email address and we'll connect them to register. After joining, they will belong to the same company.
You have entered an invalid email address. Please re-enter the email address.
This co-worker has already been invited to the Exchange portal. Please invite another co-worker.
Please enter email address
Send InviteCancel
Invitation Sent
Your invitation was sent.Thanks for sharing Exchange with your co-worker.
Link copied. Please paste this link to share this article on your social media post.
2014-04-3006:12 AM
Configuring a Johnson Controls BMS to truncate some least significant digits in received value transmitted by our energy meter
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)?