The following are some basic facts about input loop power sources: The input module usually isn't a loop power source. Although 120V is common for digital loops, other voltages are also used. There ...

There are various approaches to developing programmable logic controller (PLC) applications using experimental techniques. Modifying existing PLC ladder logic programs is another common approach ...

In our previous issue, we noted that the first step in troubleshooting digital input modules is to verify the power source of each loop. If input power is missing, the causes can be such things as ...