Connecting Power Supply -DC to GND
Connecting Power Supply -DC to GND
(OP)
On a PLC DAQ system, do you connect your -DC on the power supply to GND?
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Connecting Power Supply -DC to GND
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RE: Connecting Power Supply -DC to GND
RE: Connecting Power Supply -DC to GND
RE: Connecting Power Supply -DC to GND
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RE: Connecting Power Supply -DC to GND
RE: Connecting Power Supply -DC to GND
With the Negative grounded you always have a reference point in any grounded metal or building steel.
I think there is also an issue with instrument amplifiers becoming saturated for example if the wiring happens to be 100 Volts DC above ground (and how do you know it's not?)
I have seen systems where they had a pair of incandescent lamps in series with the center point grounded, this keeps the system referenced to ground and it does indicate if you have a ground fault but again it can have repercussions, they escape me at the moment.
Roy
RE: Connecting Power Supply -DC to GND
RE: Connecting Power Supply -DC to GND
One of my worse ones was a Lube oil heater controlled by a PLC reading a temperature transmitter 0 - 50C
The construction electricians powered down the 24 Volt supply overnight so the temperature transmitter told the PLC the tank was at zero
By the time we arrived in the morning the tank was almost boiling.
Ever since then I have always programmed heaters to shut off on over-temperature OR under-temperature
RE: Connecting Power Supply -DC to GND