line monitoring for ‘nc’ emergency push buttons
line monitoring for ‘nc’ emergency push buttons
(OP)
We have requirement of line monitoring of Emergency pushbuttons connected to UCP. Please explan how the wirirng configuration will be
What toy of E pushbutton ( no of contacts 2NO +2NC) I need o buy ?
Regards
Ayyappan





RE: line monitoring for ‘nc’ emergency push buttons
RE: line monitoring for ‘nc’ emergency push buttons
My query is E -stop is connected in NC contact meaning it is fail safe. what is the other advantage of adding a line monitoring to a fail safe wiring ?
when there cable breakage the system will trip
Please see the attachment, one vendor suggested to use EOL and In line resistor to monitor, expert comments please
RE: line monitoring for ‘nc’ emergency push buttons
If there are multiple causes that affect the system trip, a line monitor will help you or operations identify exactly what shut the system down.
So, if there are 68 items that can cause a system shutdown, you will know that it was the E-Stop that shut down the unit if it was pushed (or line break).
Assuming the line monitoring goes to a PLC/DCS that records history or a Sequence of Events recorder.....
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This is normally the space where people post something insightful.
RE: line monitoring for ‘nc’ emergency push buttons
RE: line monitoring for ‘nc’ emergency push buttons
If you use a button with 1 NC and 1 NO you can wire the NO contact back to the control panel and read it with an analog input or simple Voltmeter
One way I have seen on a 2 kilometer conveyor was to have a series resistor at each switch feeding one side of the NO switch with 1V, 2V, 3V, 4V etc when a switch was pulled by the Voltage feeding back the operator knew which switch was pulled, if 2 switches were pulled it would display the closest one first. A 4 core cable was used daisy chaining from switch to switch.
Of course if all your switches are close you can wire them all back to a common location and monitor them with a PLC inputs, whatever you do don't compromise the ability of the switches to interrupt the power to the safety shutoff device.
RE: line monitoring for ‘nc’ emergency push buttons