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Guest Davo

Quick Responce Inputs

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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.

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quote: -------------------------------------------------------------------------------- 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. -------------------------------------------------------------------------------- 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). quote: -------------------------------------------------------------------------------- I tryed setting the inputs to quick responce by setting the value of DM6628 to 2222, this did not work. -------------------------------------------------------------------------------- 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. quote: -------------------------------------------------------------------------------- I also tried as interupt by setting the value to 1111 this also has not work??? -------------------------------------------------------------------------------- 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. 240 SV area for input interrupt (counter mode) 0 241 SV area for input interrupt (counter mode) 1 242 SV area for input interrupt (counter mode) 2 243 SV area for input interrupt (counter mode) 3 244 PV area for input interrupt (counter mode) 0 245 PV area for input interrupt (counter mode) 1 246 PV area for input interrupt (counter mode) 2 247 PV area for input interrupt (counter mode) 3 See detail at PLCs.net

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Thanks Jay, I did read in the book that the pulses for Quick responce were held in a buffer untill the end of the scan, I assumed that it held all of them, not just 1 and ignore the rest Thanks for the help Davo.

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