If these are dual solenoid valves, check your program logic to make sure that you're not energizing both coils simultaneously. That's a sure-fire PLC output killer.
Once an output has been turned on or off, it will remain in that state until something tells it to change state again. Assuming that there is no other place in the ladder logic that changes the state of the output, its state will remain frozen while the subroutine is not called.
They're not really apples-to-apples. The 90-30 is closer in size and features to the SLC500 line. The PLC-5 and the 90-70 are more closely matched.
Both platforms are getting a bit long in the tooth. Neither represent the latest and greatest from their respective manufacturers. AB's current...
If that is your philosophy, then you should only purchase equipment from suppliers willing to do so. However, the fact that PLC manufacturers continue to provide mechanisms by which OEMs can protect their intellectual property is an indication that there are a significant number of people who...
This machine has worked properly in the past. The fact that it is not working properly now is not an indication that the program in the PLC has worn out.
Granted, access to the PLC program is an effective diagnostic tool, but it is not the only way to get to the root of the problem. The cause...
