Local HOA status signals to a PLC - Three PLC inputs or only two?
Local HOA status signals to a PLC - Three PLC inputs or only two?
(OP)
What is typical for sending HOA switch position status to a PLC for garden variety process control?
One signal & one PLC input for explicit status of each of the three positions, or two (Hand/Run and Auto) with Off being implied by the state of the other two? I'm thinking false status via wire breaks or switch problems.
Thanks much,
John
One signal & one PLC input for explicit status of each of the three positions, or two (Hand/Run and Auto) with Off being implied by the state of the other two? I'm thinking false status via wire breaks or switch problems.
Thanks much,
John





RE: Local HOA status signals to a PLC - Three PLC inputs or only two?
RE: Local HOA status signals to a PLC - Three PLC inputs or only two?
Keith Cress
kcress - http://www.flaminsystems.com
RE: Local HOA status signals to a PLC - Three PLC inputs or only two?
xnuke
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RE: Local HOA status signals to a PLC - Three PLC inputs or only two?
RE: Local HOA status signals to a PLC - Three PLC inputs or only two?
RE: Local HOA status signals to a PLC - Three PLC inputs or only two?
The third position of the switch, almost always the center position, is OFF. If OFF nothing is sent to the PLC or the motor starter so nothing should be occurring. You'll notice that broken wires result in NOTHING running or one function disabled which is what you normally want and is easily troubleshot.
Of course the OP has probably moved on by now...
Keith Cress
kcress - http://www.flaminsystems.com