Hello! 
I am in similar situation and found out after buying hardware that signal board did not gave an extra PTO what I needed :( 

I probably try to use similar solution what was offered but beside the relay solution I have a question: 

If I select PTO I can select between all the PLC I/O-s and signal board I/O-s 
If I now use PTO 1 for 2 axis and select different output channel from selection. 

Do I still need to make some separation with relays? 

If my 2 axis are configured for differnt I/O then I just position axis1 for example (using PTO1) then release axis (release PTO1). Enable second axis (using PTO1 with differnet output channel) position the eaxis and power it Off (release PTO1) 

could this logic work wo relay schematic?

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Split from How to expand PTO number for S7 1200.

qwazee

gtruu1

Hello! 
I am in similar situation and found out after buying hardware that signal board did not gave an extra PTO what I needed :( 

I probably try to use similar solution what was offered but beside the relay solution I have a question: 

If I select PTO I can select between all the PLC I/O-s and signal board I/O-s 
If I now use PTO 1 for 2 axis and select different output channel from selection. 

Do I still need to make some separation with relays? 

If my 2 axis are configured for differnt I/O then I just position axis1 for example (using PTO1) then release axis (release PTO1). Enable second axis (using PTO1 with differnet output channel) position the eaxis and power it Off (release PTO1) 

could this logic work wo relay schematic?

It is not clear why you wish to expand PTOs if you have only 2 axis and many outputs to link to it. What are you asking exactly? Assume you are talking to a stranger. Please reformulate your query from grass root level. 

Also mention which hardware and software is involved in your task.

Sorry sir I explain more.

Overall I have 10axis. Hardware I bought is 2x S7-1214C + 1 signal board 4DQ 24V.

My stepper drives have Pulse, Dir and enable signals for control.

Plan was to use Sinamcis motion blocks to control motor drives with PTO signal.

Now it seems the signal board was not enough to add 2x PTO so I try to find solution wo creating extra hardware cost for the project.

Seems that in the beginning I made information mistake mixing High speed output and PTO. I was able to add more High speed output but no PTO

Found the this thread which seems quite similar for my problem and added here extra question what was explained in my previous post

 Hello! Thanks for your answer!

I guess that 24ms will not be the problem this time. But I understand what you mean. In better budget project never do positioning in controller anymore except if really necessary and can use 1500T series.

So I guess there is no quick fix for my current situation? If I cannot select axis as I wanted to do another solution would be to do custom stepper control program and just using High speed outputs for position pulse

I can create even queue of using axis. Maximum 2 have to run simultaneously. At moment as I understand I can run 4 axis simultaneously per controller and I can leave 2 extra axis in queue.

I know there is many better solutions and there is taht timing and another timing which makes pain to me but at moment I just need to get it work with what I have and with standard blocks to save some time not starting implementing stepper control manually. We are talking here very simple device which needs only pulses which I have to count and digital signal to control direction.

qwazee

Saying 10 axis is not yet the full story. The situation is a bit more flexible if some are not positioning axis but rather velocity axis. Other possibilities open up like analog, communication (USS / Modbus / Profinet) or digital speed selections. Then there is the possibility of master-slave pairs.

Beyond pulse-and-direction, there is also the possibility of handling motion control by analog or by Profinet communication. The count of motion control technology blocks are limited and the allowed cycle per axis is 4ms per axis. So 6 axis x 4ms = 24ms poling time for an axis.

The Sinamics range has controllers that may be helpful to you.

 Thanks for your reply. I will try out the solution and post a feedback after few months how did it went

qwazee

You will have to evaluate the following idea.. Assume there are 8 axis which can be grouped in 2 groupings (A and B). Only one motor from a grouping can run at a time.

Stepper A1 (motor 1 of grouping A) and stepper B1 cannot work at the same time. A1 and B1 however share Q0.0 and Q0.1 which is the pulse-and-direction pair. Both A1 and B1 is wired to Q0.0 and Q0.1.

Q0.0 and Q0.1 is declared as PTO1 and controlled by the technology object "AxisAB1". The enable output of "AxisAB1" is routed to memory bit M0.0.

Q0.0 and Q0.1 is declared as PTO1 and controlled by the technology objects "AxisA1" and "AxisB1". The enable outputs of the two technology objects are different.

A1 and B1 has different enable signals, respectively sourced from Q2.0 and Q3.0. The state of M0.0 will switch Q2.0 or Q3.0 depending on which motor is scheduled to run.

When switching from A1 to B1 the following happens:

• The current position of A1 is saved.
  
  
• MC_POWER of "AxisAB1" is disabled.
  M0.0 -> FALSE, Q2.0 -> FALSE.
  
  
• < Motor B1 is selected internally >
  
  
• MC_POWER of "AxisAB1" is enabled.
  M0.0 -> TRUE, Q3.0 -> TRUE.
  
  
• Direct absolute homing is executed to restore
  the previously saved position of B1 into "AxisAB1".
  
  
• Use other motion control tasks as needed for B1.

EDIT
It is possible to create technology objects that uses the same PTO. It is then not needed to do the tasks as explained above. You can only switch between technology objects.

Also see the appendix in the function manual
[SIMATIC STEP 7 S7-1200 Motion Control V6.0 to V7.0 in TIA Portal V16]
for some application notes

(a) Using multiple axes with the same PTO
(b) Using multiple drives with the same PTO