Pico inputs?

Hello everyone! It has been a while since I've been on.

I was hoping that i could get some info on how to connect potentiometers to a Pico PLC in order to control timing of a circuit?
Here is what I am trying to do....

I have an old food vacuum machine that the timing PC board went bad on. Rather than trouble shooting the board, I would rather install a Pico controller to run this operation.

I do not understand how to use the potentiometers for the vacuum time and the seal bar time as analog inputs to this type of controller. The PLC I am thinking of using is a AB-1760.

Does anyone have experience with this unit and can tell be how to use the Pot's as inputs.

I'd like to learn more about the input theory ( analog and digital ). Any suggested reading?

Thanks Barry.

Barry,

Typically, the idea of the potentiometer is to reduce or increase the time it takes to charge a capacitor. Once the capacitor is charged to a voltage that will activate a timer then the timer runs.

In order to use a potentiometer as an input you need to use an analog input on the PLC. This is the Set Point. You need to convert that signal to a time-value. You then need to provide a means to indicate how long the particular condition exists. This can be done with a vacuum sensor. When the vacuum exists, the input turns on. Then you run a timer in the PLC. The timer value is based on the analog input from the potentiometer.

The Pico user manual has a diagram on how to connect a potentiometer:

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The problem is that, as far as I know, you can't use the analog value as a timer's preset. You can only use them in comparison instructions...

This is why a Pico is called a 'programmable relay' and not a PLC... :nodi:

beerchug

-Eric

ok

Hi Barry I see Eric has addressed the pico. What kind of signal is feeding the old timing pc board? If it is digital = a contact closes then the pc board times out and does something esle. You could use this same signal to the pico and let it do the timing. If it`s an analog signal to the pc board there are some inexpensive controllers that will take analog Crouzet makes one.
http://www.crouzet-usa.com/