pulse train output

[ecampos]

There is a machine in my plant with an obsolete Omron PLC in it that I need to replace. One of the outputs from this PLC is to a stepper motor drive, I will need to replicate this function in the new controller. I have no experience with stepper motors or drives and I seem to have hit a dead end in my research. I have a feeling that I am not searching for the right terms here, so any direction would be appreciated. Here is the description from the stepper drive manual for the function in question:

Step Clock Input - A positive going edge on this input advances the motor one increment. The size of the increment is dependent upon the settings of the resolution select switch SW1.

The instruction in the Omron program that I believe is writing to this output is @PLS2(887).

So I believe that this must be outputting a train of pulses to the stepper drive so that it knows how far to run the motor. I was expecting to find a required pulse frequency in the drive manual, but there doesn't appear to be one. Is this something that is common amongst stepper drives and therefore not included in this manual, or should I try to reach out to the drive manufacturer for more detailed information?

I don't have much experience with Omron PLCs so I am hoping to replace this one with either an Allen Bradley product, or an Automation Direct P2000.

I am sure there must be a direct equivalent for this @PLS2(887) instruction in the AB or AD world, can anyone tell me what it's called!? I have searched for pulse output, high speed output, pulse train, etc and I am coming up short. I did find that there is a PTO instruction for some of the MicroLogix controllers that seems to be what I am looking for, but I can't find anything like that in the Logix5000 or P2000 instruction sets.

 

[dmargineau]

The Allen-Bradley MicroLogix 1100, 1200, 1400 and 1500 CPUs are using RSLogix 500 for configuration/programming; the dedicated instructions for Pulse Train Output functions are 'PTO' and 'PWM'.

Also, the Micro800 processor family provides PTO functions; the dedicated configuration/programming software for the Micro800 CPUs is Connected Components Workbench (CCW); free at

http://compatibility.rockwellautoma...umb=112&refSoft=1&toggleState=&versions=55972

 

[gclshortt]

In AD it is called a Pulse Output Signal.
https://cdn.automationdirect.com/static/manuals/d1user/ch3.pdf

In AB is is called a Pulse Train Output. (PTO)
http://literature.rockwellautomation.com/idc/groups/literature/documents/at/2092-at001_-en-p.pdf

What model of Omron PLC do you have? The maximum frequency that can be specified
depends on the model and pulse output support. You must refer to the Omron Operation Manual to get the specifications.

Regards,

 

[Doug-P]

In AD's Do-More Designer (free download) this is referred to as pulse output, a high-speed I/O function.

 

[ecampos]

The Allen-Bradley MicroLogix 1100, 1200, 1400 and 1500 CPUs are using RSLogix 500 for configuration/programming; the dedicated instructions for Pulse Train Output functions are 'PTO' and 'PWM'.

I did come across this, are those instruction the same on the Logix 5000 platform though? I have used some MicroLogix in the past, but I was told that the RSLogix 500 controllers are heading towards obsolescence so I was thinking of using a CompactLogix for this machine.

What model of Omron PLC do you have? The maximum frequency that can be specified
depends on the model and pulse output support. You must refer to the Omron Operation Manual to get the specifications.

The unit I need to replace is an Omron CQM1. Manual says it can output pulses up to 50Khz. So I take it I need to find out what frequency my stepper drive requires and make sure whatever controller I use can handle that? I wasn't sure if this was common knowledge or drive specific.

 

[dmargineau]

I did come across this, are those instruction the same on the Logix 5000 platform though? I have used some MicroLogix in the past, but I was told that the RSLogix 500 controllers are heading towards obsolescence so I was thinking of using a CompactLogix for this machine.

MicroLogix CPUs are not part of the Logix Class controller family hence they do not use RSLogix 5000 for configuration/programming; RSLogix 500 is not going anywhere anytime soon; there are hundreds of thousands (millions?) of SLC and MicroLogix controllers running all over the world and still available for new purchases.

The modular CompactLogix platform provides only third party PTO capabilities:

https://www.amci.com/plc-automation-products/3602-compactlogix-motion-controller

 

[ecampos]

The modular CompactLogix platform provides only third party PTO capabilities:

https://www.amci.com/plc-automation-products/3602-compactlogix-motion-controller

That's the piece I was missing. Thanks!

 

[just the cowboy]

How much other IO

How much other IO do you have? AD makes a DL05 brick unit that has built in high speed output, 8 in 8 out plus one slot for more, under $200. I have used them in this way for a few years no problem. The Prod 2000 is super easy for simple moves but will run about $800. I am using both for motion no problems.

 

[ecampos]

49 inputs, 25 outputs, 1 HS input (encoder), 2 HS outputs (stepper drives). Although I think I will eliminate many of the inputs by putting an HMI on this thing.

I am going with a P2000. I am already familiar with the programming software, and I found out about the high-speed input and output cards and the Simple Move (SMOV) instruction. This is still way cheaper than replacing with a CJ2M or CompactLogix which are the other 2 controllers I was considering.

 

[Gene Bond]

I was expecting to find a required pulse frequency in the drive manual, but there doesn't appear to be one. Is this something that is common amongst stepper drives and therefore not included in this manual, or should I try to reach out to the drive manufacturer for more detailed information?

The input pulses for the stepper driver are 1:1 with the motion of the stepper motor, so you vary the speed by the frequency. The steppers are X pulses per revolution, or X degrees per pulse, so its pretty easy to figure the rpm.