ML1100 RS485 32bit float

Hi all i have a new ML1100 + breakout adaptor and am connected over RS485 to a schneider PM710MG power meter slave.

Does anyone know if i can read a 32bit float holding register (more accurately two 16 bit registers that together form the float) and read them directly into my float data file?

I tried it but it didnt work.

I did use an alternate method which does work. I had to go the long way round, configured the msg to place the data in two integer registers, unfortunately had to do an endian swap and then finally a copy into the float data file. Sorry forgot the error code, but the jist of it was the local unit (PLC) was unable to process the response. I checked the message packets with a com sniffer and the send / recieve contents are identical for both methods.

Thanks, Nathan

The MicroLogix 1100 implementation of Modbus RTU is oriented toward the classic Integer holding registers; the MicroLogix files into which Modbus data is transferred are always Integer registers.

Since byte swapping and endian-translation are so common in Modbus, the method of bringing in Integer registers then manipulating them is the usual solution. That's one of the reasons for the CPW (Copy Word) instruction in the MicroLogix, which has fewer datatype compatibility restrictions than the classic COP (Copy) instruction.

Thank you Ken