Omron or AB virtual 360 deg encoder

Hello, I have currently been programming Omron and some AB plc's for about 15 years but I am faced with a completely new task that scrambles my mind. I am wanting to use either a micrologix 1200 or a Omron CJ1M or CQM1 plc and program in a virtual 360 degree encoder. Im thinking it would consist of a counter set to #0360 and regulating the speed of the pulses to the counter would regulate the speed of the vurtual encoder. I am finally in the end, wanting to regulate that speed between .5-60 sec/vurtual rev. This is 1 to 120 RPM's of the vurtual encoder. Any help in doing this would be greatly appreciated. This is my first post on this site so let me know if you need any more information.
Thanks!
Randy

Welcome to the foorum Randy

Are you using this in a motion application?
How do you plan to regulate the speed to the virtual. Remember things like scan time COULD effect how you are going to handle this. I am not saying it will I am saying it might.

I don't do Omron so I can't help there.

Can you upgrade to a Rs 5000 family system they have a true virtual axis.

Thanks for your reply. I will be using this to operate a peice of equipment. The machine will do certain things at different degrees of the virtual encoder. The operator will be changing the speed of it through a HMI which will change the cycles/min. I only have at my disposal micrologix, slc503, omron cqm1, or omron cj1m. I know that scan time can affect it some but in this application, I don't believe it's going to be enough to matter. The entire cycle time will only very between 1 to 120 cycles/min. Any other questions, I will be glad to answer.
Thanks again!

THe scan time is program dependant. So no matter how fast your process runs the PLC program will be the master. What happens if the update rate is variable? 120 cycles/min and 360 RPM equals 43200 ppm I think. So if the update rate varies from scan to scan would that effect your "machine doing certain things at different degrees of the virtual encoder." Are you using this on a press? You could use a STI and PLS inside the MLX.

OMRON CJ1M
Use one of the high speed Pulse outputs wired to one of the High Speed Counter Inputs.
This will be completely independent of PLC scan time.
Change velocity of the Pulse output by using SPD instruction.
Set up the high speed counter input to reset at 360 counts. I think you do this by configuring it for Circular in the PLC settings. [Don't have the manual handy right now].

That sounds like a great idea! I think the CJ1M has 2 high speed counters. I will research how to do the ladder.

Tested this morning. Works just fine.
Modify PLC settings "Built-In Input" as follows:-
"High Speed Counter" Check box.
"Counting Mode" Circular Mode
"Circular Max Count" In your case 360 for your virtual encoder.
"Reset" Software Reset
"Input Setting" Increment pulse input.

Transfer settings to PLC.
Don't forget to POWER DOWN and POWER UP to accept the above changes.

There is no need to modify the "Pulse Ouput" settings as you will be using the SPED[885] instruction.
For Pulse output 0 Configure SPED[885] as follows:
Port specifier #0000
M:Output mode #0000
F:First Pulse Frequency Word. This is the speed you want to run at. It can be a fixed Hex value entered as #**** or a fixed Decimal Value entered as &**** or any data memory area. For example if you assigned D100 to F: then changing D100 will directly effect the pulse output speed when the SPED instruction is active.

That sounds very simple and should work just fine! Im going to do some testing this weekend myself and get a running version of this. Yes they will change the speed in a DM and the screen will access that DM. I do appreciate everyones input on this.
Thanks again,
Randy