Plc Modbus

Hi

I am using a directlogic PLC to read the massflow from a Krohne massflow meter connected via RS-485 and using MODBUS. The massflow meter manual says that the massflow value is located atholding register 20014, however the PLC wont allow me to enter in this address as it says that this is not a valid address for function code 3. it says the only valid adresses for this code are 40001-49999. Any suggestions on how to fix this problem?

Thanks

This might help, it's AD's modbus conversion excel application.

http://support.automationdirect.com/docs/modbus_conversion.xls

It is located on this page on AD's website http://support.automationdirect.com/technotes.html

Try setting up your Modbus command to read holding register 40014 (or 400014).

Function code 3 is a command to read multiple holding registers. In a Modicon PLC, that would be address 4xxxx. If the manufacturer of the flow meter wants to use an address of 2xxxx, that's up to them. When you get down to the details of the protocol, you set up function code 3 with an offset from the start of the holding register memory area and the number of bytes to read.

Hey Guys

Thanks for your advice. I only work on Fridays, so will have to wait a week to try it out. Hope it works. Thanks