05-28-2015 03:16 PM
I am connecting to devices via the NI Modbus Library 1.1.5.39 for LabVIEW. I am using a Modbus Serial Master and can create the connection correctly. When I try to read either Input or Holding registers I get the following error:
I know that the communication works with the device because the vendor provided a simple software that can successfully connect and read all the data.
05-29-2015 01:44 AM
Hi,
ModBus communication uses a slave address to identify the different slave on a network. Also if you have one slave you must specify the slave address.
With slave address 0 (zero) the ModBus message is a broadcast message. A broadcast message is for every slave, therefore there is no response expected from the slave(s).
So specify a slave address.
Kees