Micrologix 1000 High Speed Counter (HSC) Issue

[Craig Chamberlin 1]

Hello everyone, I have been attempting to connect a Dynapar 600PPR encoder to the high speed input on my Micrologix 1000 PLC. According to the manual, this is I:0/0 and it is rated for 8KHz. I did the following math to ensure I was within that frequency range. 600 RPM Max Speed / 60 Seconds = 10 Rotations per Second 10 Rotations per Second x 600 Pulses per Rotation = 6000 Hz 6000 Hz / 1000 = 6 KHz This should give me a 2KHz leeway. According to the Micrologix 1000 Manual (Chapter 12) on High Speed Counters and the Help Section of the software, configuring the high speed counter to count pulses requires placing the HSC logic on a rung with no conditionals. I have done this. The program I created has only this counter to test my encoder input. Channel A of the encoder is wired to Input 0/0. The encoder is powered with the local 24 volt power supply from the Micrologix. This issue: When I download the program and place it in run, the counter can only count at the same rate as a regular counter (to test this theory, I placed a regular counter below it, wired channel B to input 0/1 and it counts at the exact same speed) For some reason the HSC isn't utilizing itself as a hardware counter. Now I've been digging through manuals for instructions for hours to try and find out why the counter will not count my pulses fast enough. Now I am assuming this is some stupid small setting I do not have configured properly. My Hardware: Dynapar H42-0600 Encoder Micrologix 1000 1761-L16BWA I have attached a copy of my program to this post. Any help would be much appreciated, I'm ripping my hair out this morning :D Thanks again! Craig Chamberlin Precision Electric, Inc. HAMPTON ML1000 REV 2.RSS Edited 11 Nov 2010 by Craig Chamberlin

[J. B. Jennings 4]

From the Micrologix 1000 Manual:Publication 1761-6.3 July 1998 "One difference between Up Counters and Bidirectional Counters is that for Bidirectional Counters the accumulator and preset values are not changed by the high-speed counter when the presets are reached. The RAC and HSL instructions must be used for this function." Hope this helps

[b_carlton 61]

Under I/O configuration choose 'Filter Adjust' and set the filter on the input points to suit the encoder rate. Then download the program to the Micrologix.

[Craig Chamberlin 1]

You're the man! I cannot believe I didn't catch that part in the chapter (it is in the about section) and is rather obscurely discussed. I really appreciate the response. Thanks again!

[joser 0]

Hi Carlton I am not aquited with the HSP, but what was the encoder rate , you suggested set the filter to suit the encoder rate, what is that rate? 6 Khz?

[b_carlton 61]

Yes, he analyzed his rate at 6khz or about .16 milliseconds. The filter should be set for a time about 1/10th of that if possible.The default setting is in milliseconds. Edited 9 May 2014 by b_carlton