Quick responce inputs

I am trying to connect 3 encoders to inputs 0.03 0.04 0.05 on a CPM2A PLC I am only using the A phase of each encoder as I only need to count pulses to get a measurment one pulse = 1 mm.
I tryed setting the inputs to quick responce by settind the value of DM6628 to 2222, this did not work. I also tried as interupt by setting the value to 1111 this also has not work???
Can anyone advise me what I have done wrong, or have failed to do.

Regards and thanks
Davo

PS the speed I need is about 1.5 Khz, best I can get is 0.5Khz.

Have you checked your scan time?
if you can get 0.5khz then your scan time is less than 2ms, pretty fast by PLC standards.
It's not likely that you'll get it any better than this.
You should use a high speed counter card.

Doug

Scan time is less than 2ms, it is a small program.
There is no high speed card for this model omron, however in the good book they state that four inputs (from 3 to 6) can be set to 2khz by placing 2222 in DM6628 ??? I have done this and it does not seem to work, I hoped somebody may have done something similer to this and know the secret...

Thanks for the reply Doug
PS I am in Melbourne

Davo

I am trying to connect 3 encoders to inputs 0.03 0.04 0.05 on a CPM2A PLC I am only using the A phase of each encoder as I only need to count pulses to get a measurment one pulse = 1 mm.

Click to expand...

Count-up Interrupts Using Interrupt Inputs (Counter Mode)
Interrupt inputs (counter mode) are counters based on inputs to the CPU Unit’s built-in points 00003 to 00006. These counters have four points, and they can provide either an incrementing(0000 to FFFF) or decrementing (FFFF to 0000) count depending on the mode setting. Since this function utilizes interrupt inputs for counting, it is not possible to use the same inputs for other interrupt inputs. An interrupt subroutine is executed each time the condition is satisfied that the counter PV equals the counter SV (in incrementing mode) or 0 (in decrementing mode).

I tryed setting the inputs to quick responce by setting the value of DM6628 to 2222, this did not work.

Click to expand...

Quick Response Inputs are catch and hold type inputs. Four points (Min. input pulse width: 50 ms max.) They are good for fast moving single pulses which are "trapped" and then presented to the plc each scan. If more than on pulse is presented to the input during scan, the additional pulses are ignored.

I also tried as interupt by setting the value to 1111 this also has not work???

Click to expand...

Just setting DM 6628 to 1111 does not increase the response time of the input. It sets the inputs to become internal counters which have presets and trigger interrupt subroutines when reaching preset.
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Thanks for your help Jay
I used the INT instruction and it now seems to be working fine.
Davo,