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Maximum Response Time


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Hi,

I will be using V1040 with around 64 Inputs, 64 Outputs & 12 Analog Inputs. The actual usage would be around 30 Inputs, 24 Outputs & 8 Analog Inputs.

The process involves comparing the 8 analog inputs and carrying out the associated procedure. The analog inputs are connected to sensors which have an output response time of 75 microseconds in the 0 to 10 V range.

What will be the PLC's scan time for such a configuration?

Pl comment.

Ron

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Hi Ron,

I think the "bottle neck" here is not the PLC scan, but the conversion time of analog inputs.

Which hardware you're using for analog inputs? Did you check the conversion method and conversion time for the relevant hardware unit?

The scan time of te controller itself depends not only from the numbers of inputs and outputs, but the length of the program and type of operations. HMI also can affect a little the scan time.

Usually gthe "normal" scan time for enhanced Vision OPLC is in range 3-7 ms.

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Hi Ron,

I think the "bottle neck" here is not the PLC scan, but the conversion time of analog inputs.

Which hardware you're using for analog inputs? Did you check the conversion method and conversion time for the relevant hardware unit?

The scan time of te controller itself depends not only from the numbers of inputs and outputs, but the length of the program and type of operations. HMI also can affect a little the scan time.

Usually gthe "normal" scan time for enhanced Vision OPLC is in range 3-7 ms.

Thanks Emil,

I will be using 2 X IO AI8 in the fast mode. It mentions 25mSec per input. What does it mean? 8 inputs would take 200mSec?

Pl reply

Ron

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Hi Ron,

As stated in document , "Conversion time 100mSec minimum per input in Normal mode", "Conversion time 25mSec minimum per input in Fast mode".

So for 8 Analog Inputs in a Fast mode conversion time will be 25mSec*8=200mSec.

As IO-AI8, communication between it and OPLC, and OPLC itself works without synchronization, you need to add communication time ~20 mSec and OPLC scan time as Emil stated.

The other forum topic discussing the same issue will be interesting for you:

http://www.unitronics.com/forum/topic.asp?TOPIC_ID=1362

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