Does the Fisher locator not function below 40%?
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I have a Fisher locator here; it stops working whenever the level falls below 40%. The valve operates in a FC mode, the voltage on the control circuit is 26V, and the circuit isn’t grounded. A ground check with a megohmmeter shows no problems, and with a Fluke device the valve can be opened and closed properly. Once it’s connected to power, everything works fine – but why does this problem occur again the next day? I’ve also replaced the card key in the center control unit, and there’s no problem. Could someone with expertise please explain why this is happening?
Re-calibrate the locator; if that doesn’t work, replace it. The problems are always the same: the wiring, the output, the connections – the hardware itself. You’ve already checked the cards and wires. If there’s no interlock issue, then the only solution is to replace the locator
First, check the input of the locator. If the locator receives an input signal but does not operate, the problem lies with the locator itself; check whether it is stuck at a level below 40%.
As for intelligence, who can really say for sure? One can only use the process of elimination – the wires, cards, and signals are all fine, so it must be the locator. Although you said that losing power might work, it didn’t work later on; from this situation, it seems like it’s frozen. I suggest you replace it, since you’ve already tried to recalibrate it.
Below 40%, the current is relatively low – is it possible to have interference?
”It will be able to operate again after a power outage. After approximately how much time will this problem occur again? You can use a Fluke device to send a signal and wait for the same amount of time to see what happens Personally, I think it’s a problem with the locator motherboard
If the Fluke tests are normal, there should be no issues with the valves or positioners. Could it be that the DCS has output limiting?