My setup:
cRIO 9082 running the attached VI in RT Engine
NI 9148 Ethernet RIO Expansion Chassis
NI 9871 RS485 module in the expension chassis
Multitek Multigen M820 meter with an RS485 output
I am trying to read in the voltage and current values output by the Multitek. I have wired the +/- RS485 output on the back of the Multitek to both the green pair and orange pair on an ethernet cable and plugged the ethernet cable in to the NI9871 module. I wired both green and orange because I don't need to transmit, so I wired both together just to be extra sure I got the right pair on there.
Application:
I have attached the VI I made to test this communication. I initialize the VISA ports as a 2Wire configuration and initilize the modbus protocol with matching settings to how I've set up the Multitek.
I have also attached the Operating Manual for the Multitek. RS485 setup starts on page 23 and the registers I want to read are on page 80. I have matched all RS485 settings and outputs the the VI I made.
When I run the application, I get no errors during initialization. The only error I get is a timeout error on the Modbus Read VI and nothing out of the registers.
Is there anyone on here who has more experience than I do with modbus who can point something out that I'm doing wrong?
Thank you,