Hi Guys,

I have an OB1 that contains these Blocks: Main SFC (graph) and "Home Linear Axis" (graph), plus more but we keep these 2 as an example for now. Main SFC block has no input in "EN" or "ENO," while "Home Linear Axis" has EN = "Start Homing Linear Axis Block"  bit and ENO = "Homing Linear Axis Block Complete" bit.

My problem is in "Main SFC" block, when I call "Home Linear Axis" block by enabling "Start Homing Linear Axis Block"  bit by using "N" or "S" Qualifier in the STEPS, it does not start the "Home Linear Axis" block. 

Is there extra settings that I need to set or reset for the block to be called inside the MAIN SFC block?

Thanks in advance.

I'm currently using Simatic s7-300 series: CPU315F-2 PN/DP 

Does this cpu allow block access? the help file says standard access.

Kind Regards,

Billy

Hi BillyK,

from the pic you posted I dont see any problem - it should work. Have you gone online to check if %M0.1 gets green when it is set in graph? You should check in graph as well as where you call FB1.

If %M0.1 is set, you would have to look inside FB1 (online) to check why it is not working.

I personally avoid %M0.0 to %M0.7 as these markers are often used for other purposes.

regards

Hi eisenpferdreiter,

Simulating it works as you instructed, but the step does not wait until the block that is call to finish. It jumps to the next steps and so on.

However, I found this 

https://support.industry.siemens.com/cs/mdm/54430386?c=35004217099&lc=en-US

And works on the simulator, I haven't had the chance to try it on the machines yet but looks very promissing.

Kind Regards,

Billy

BillyK

Hi eisenpferdreiter,

Simulating it works as you instructed, but the step does not wait until the block that is call to finish. It jumps to the next steps and so on.

However, I found this 

https://support.industry.siemens.com/cs/mdm/54430386?c=35004217099&lc=en-US

And works on the simulator, I haven't had the chance to try it on the machines yet but looks very promissing.

Kind Regards,

Billy

Hi Billy,

yes, the step will not wait, as %M0.5 will immediately be set by ENO.

When you start FB1 it will for sure take more than just one cycle till the homing is done. But the ENO will be set immediately when FB1 is completed in first cycle. Thus ENO will come way too soon for using it as condiion for transition 3.

You should set %M0.5 when homing linear axis is really done and not by ENO.

regards

Hi Billy,

yes, the step will not wait, as %M0.5 will immediately be set by ENO.

When you start FB1 it will for sure take more than just one cycle till the homing is done. But the ENO will be set immediately when FB1 is completed in first cycle. Thus ENO will come way too soon for using it as condiion for transition 3.

You should set %M0.5 when homing linear axis is really done and not by ENO.

regards

 

 Hi eisenpferdreiter,

I have actually tried that before, but it seems that it can only do one cycle then again jumps around.

Even though I have reset and set the BITS correctly.

Hopefully, when I can download my current program to the PLC every thing works.

I'll update you soon. Thank you for your help. 

Kind Regards,

Bill