Encoder input module in PLC

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Thread Starter

sensorless

We are using EZ Automation PLC in our plant in India. We have to add an encoder in the control system and connect it to the PLC. Please advice is it necessary to use HSDCI (High speed digital input module) in PLC?

Can not a normal DI module be used for this (to minimize the cost factor)? Please advice. I would appreciate if someone can clear my concept in this regard.
 
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Bob Peterson

You have to look at a couple of things.

One is whether you need a quadrature signal or whether a simple pulse is adequate.

Another is how fast the encoder pulse is.

if you do not need a quadrature signal and the pulse is slow enough that the standard DI can capture it, you can use the standard DI.

According to the web site the high speed module is $27. If you do not need a quadrature signal and the standard DC input is not fast enough and the high speed input is fast enough, then spend the $27.

It does not appear to me from looking at the web site the the $27 module supports quadrature signals so if you need that you would have to buy a $99 counter module.

Even the high speed DC input module appears to be only good for about a 1.5 kHz signal. The std DC input looks like about 150 Hz is its top end. And that is if the CPU can keep up with the module.

The counter can go to 100 kHz.

--
Bob
http://ilbob.blogspot.com/
 
S
> You have to look at a couple of things.

> One is whether you need a quadrature signal or whether a simple pulse is adequate.

Quadrature signal is needed.

> Another is how fast the encoder pulse is.

The encoder to be used is of 1700 ppr.
 
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