I must not be entering the correct value for one of the fields. I assigned a modbus address in the Pac and when I did it gave it a start modbus address of 400001 and an end Modbus address of 400002. When I look at the tag in the data viewer it shows a modbus address of 400001. When i enter 400001 into the modbus address field in the gateway it gives me an error shown in the screen cap and then chops the 1 off leaving me with 40000. Thanks