RSLogix Axis Question

Hello,

I’m working with a virtual axis in RSLogix and I have code using the .ServoActionStatus of data type AXIS_VIRTUAL. I can’t for the life of me figure out how to disable this bit. There are no active motion instructions sent to this axis but it is sent a Motion Axis Stop instruction once. The code I am using was originally designed for a physical axis.

Is there any way to disable this bit for a virtual axis, or is it always active because it is a virtual axis so it would always be under servo control?

Apparently it is Read Only; I have tried to type "0" within the Edit Mode of the Offline CPU Tag database and RSL5K raised hell.
If you have a "live" system in your hands, cross your fingers and try a "hot rung" with an OTU of the "Your_Axis.ServoActionStatus" BOOL tag...
The only reference I have found (except the examples for the Motion Axis Move instructios when it is being examined only)
is at page 61 of http://literature.rockwellautomation.com/idc/groups/literature/documents/wp/motion-wp001_-en-p.pdf

This tag has "status" in it's name. I tend to think that "status" inherently means it is read only - the drive is giving you feedback to it's current condition. Similarly, you wouldn't be able to change the drive "speed feedback" or "current feedback".

If you want to affect the axis status, you will need to give it some sort of legitimate command. Not sure if you can turn a virtual axis on or off. You should be able to do things like Jog and Move.

The ServoActionStatus bit is read only and is always on for a Virtual Axis. A Virtual Axis is always under servo control.

I am not sure what the problem is. You should set up your logic so that if the axis is Virtual, then you don't need to 'use' this bit. In fact, if you use an MSO instruction, it will ERRH out.

abwiz said:

The ServoActionStatus bit is read only and is always on for a Virtual Axis. A Virtual Axis is always under servo control.

I am not sure what the problem is. You should set up your logic so that if the axis is Virtual, then you don't need to 'use' this bit. In fact, if you use an MSO instruction, it will ERRH out.

Click to expand...

I did find out that this was the case.

The reason I was asking was due to a programming architecture that implements MSO motion instructions dealing with real axes. I was trying to test a virtual axis and was curious if I could "de-activate" the virtual axis so I didn't have to modify the code more that I had to.