Application Notes

EAP-032136

How to invert valve control signal 4-20mA

We installed a control valve at field. This valve works with control signal of 4-20mA.

After installation, we found that the valve moves to open/close in the opposite direction of increase/decrease of 4-20mA. To solve the problem, we know we have to change operation mode of the valve. But the valve is already installed in a pit, which is too much narrow space for us to reach. As second best solution, we suppose we have to invert the manipulating signal 4-20mA to 20-4mA to match the valve action. Does M-System have any suitable transmitter for this application?

We’d like to introduce our inverted output transmitter, model M2UDS to meet your request. Please specify the M2UDS with input code “A” (4-20mA) and output code “A” (20-4mA). This transmitter provides a reversed output proportional to the input signal and this can solve the problem without changing the valve action mode.