How do you program the "Overlay Mode" (Mode = 2) for the MC_MoveAbsolute technology function in TIA.

This option was available in the the classic S7-Technology.

With S7-Technology's MC_MoveAbsolute, Mode=2 is blending motion.

With S7-1200/1500 motion control this possibility does not exist at the moment, there is no blending motion up to now.

Regards,
daviso

daviso

With S7-Technology's MC_MoveAbsolute, Mode=2 is blending motion.

With S7-1200/1500 motion control this possibility does not exist at the moment, there is no blending motion up to now.

Regards,
daviso

Hello.

Could you please point me to a manual that explains what the blending does? I hope to understand better what the topic starter asked.

The S7-1200 / S7-1500 does have 'blending' -- if I understand it correctly. The TO_CommandTable hints at it.

The motion control manual also hints at it when making an example of MC_MoveAbsolute and MC_MoveRelative. Executing a second motion control while the first is busy, will have the second triggered motion take over from the first.

Does this help or are we having a communication gap?

@qwazee: There you go: https://support.industry.siemens.com/cs/gb/en/view/30119663/25336958731

Blending basically means that the new command (that is triggered with mode 2) does not abort the current command, but instead the motion blends from the currently active one to the second one. The linked example describes this quite well.

And yes, I'm with you regarding S7-1200 command table, with this you should get at least something very similiar, though I think there are little differences (very little).

But with S7-1500, there is no such option. When you trigger a new MC_MoveAbsolute, the currently active one will be aborted as soon as the new command is triggered. But this is no blending.

Just think of a MoveAbsolute from position 0 to 1000, second MoveAbsolute with target 500.

With blending you would ensure that the first MoveAbsolute would finish and position to 1000, then blends over to the second one and moves back to 500.
With S7-1500 motion (where no blending exists at the moment), the second MoveAbsolute would abort the first one when it gets triggered, so you would never reach position 1000. To achieve this you need to wait for Done=TRUE feedback and only then trigger the second command, but this is no blending then.

Regards,
daviso

@daviso: Thank you. The information you supplied helps very much.

Putting "blending" as search word in the software help does have some hits, but unlikely something that screams "helpful". Because blending can be done via the TO_CommandTable, I suspect coding can achieve the required outcome.

BUT only a rough approximation might be possible for the S7-1200 because of the 'slow' update rate of the motion control routines. The S7-1500 may be better.

I did not see the 'mode' pin on the MC_MoveAbsolute instruction when using motion control on (for example) the CPU314C controller. Perhaps @BioMaM should contact Siemens and ask them for more insights.

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@qwazee: The blending functionality the OT reffered to comes from S7-Technology, so is only available on S7-300T PLCs. The C-CPU you looked at does not offer this functionality at all. I assume you checked with Easy Motion Control on the S7-300 C-CPU, but this is something different.

Regards,
daviso

 Hello.

daviso

@qwazee: The blending functionality the OT reffered to comes from S7-Technology, so is only available on S7-300T PLCs. The C-CPU you looked at does not offer this functionality at all. I assume you checked with Easy Motion Control on the S7-300 C-CPU, but this is something different.

Regards,
daviso

That is super helpful. That note pointed to a migration guide seen here:
Migration Guide: S7-31xT to S7-1500(T)

The document within has something to say. An extract attached.
The the last note is of value to the topic:

~

Hey qwazee.

Thanks for the link to the migration guide....... there we have it in writing from Siemens. So I don't have to look any further 

..... I assume I must find a way of programming this feature myself. 

BioMaM

..... I assume I must find a way of programming this feature myself. 

 I don't really see a chance with S7-1500 motion control.

This does not have the TO CommandTable mentioned by qwazee, so this is no option.

Also most commands just abort the currently running one. Which new commands abot which running ones is shown here: https://support.industry.siemens.com/cs/de/en/view/109781849/130685436171

You might try with gearing, perhaps a TO Cam to get the motion sequence by using camming and having the provile you want implemented in that cam, but that would also require another leading axis (but this could be a virtual axis).

S7-1500 T PLCs have the MotionIn commands, where you generate the whole setpoint curve yourself, so with this you're extremely free when it comes to defining the motion. But on the other hand this requires more efforts on your side. For information on the MoitonIn commands see here: https://support.industry.siemens.com/cs/de/en/view/109781849/138120296971

If you don't need this to work very accurately, you could try to just execute the second command a the right time, but I don't think this is really a good solution, for me this is just too timing-based, which I would avoid.

But honestly, if you find a suitable solution, share it with us, I'd really be glad to be proven wrong 

Regards,
daviso