Fusing of Instrumentation signals
Fusing of Instrumentation signals
(OP)
We have a customer who has asked that "all signals entering the panel should be protected by a fuse e.g WSI 6 110Vac".
In our panel we have a pr5225 module and a PR531 for temperature out in the field we have a speed sensor and RTD's. Has anyone seen this before? is it really necessary?
Thanks
In our panel we have a pr5225 module and a PR531 for temperature out in the field we have a speed sensor and RTD's. Has anyone seen this before? is it really necessary?
Thanks





RE: Fusing of Instrumentation signals
My shop builds UL panels. If you could provide some data (what's a pr5225, are these Class 2 circuits, etc...), we might be able to help out more.
Best to you,
Goober Dave
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RE: Fusing of Instrumentation signals
1. Keep their I/O cards from being damaged due to field side shorting to ground.
2. They are looking for away to isolate for field service.
3. Just a broadband spec that they apply to every thing.
In any case, if the RPM sensor is Hal-Effect over TTL, I would avoid any additional products between I/O and sensor. The extra “weight” of the fuse may degrade the signal. The same goes for the RTD even if it was 4-wire, every junction is one more failure point and additional resistance.