EPOS active homing at hardware limit switch

TechTeam

Hello,

how do you do the homing? Do you use Technology objects inside the PLC to home the axis or do you have the position control inside the drive (e.g. using Basic Positioner)? And what kind of encoder is used (absolute singleturn / absolute multiturn / incremental)?

When using the position control inside the drive and you have an absolute encoder, you can home via p2507 = 2 (it changes to "3" automatically when finished) and then copy Ram to Rom with the drive.

 We need to home the axis as homing encoder cam and encoder zero mark mode. Also need to use reverse cam switch as reference switch in epos. Can you instruct us how to do that?

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Split from After power failure Servo homing problem.

TechTeam

Hello,

so it seems you have an incremental encoder, right?

I am just asking because sometimes the machine is equipped with absolute encoders and could easily be adjusted retentively, but the programmers try to do an active homing procedure, which is not necessary in that case.

So what you want to do is an active homing. The axis is moving to the proximity switch and with the next encoder zero mark the axis is homed. You need to know that this type of referencing is not stored inside the drive! After Power Off/On you will need to do the homing procedure again. Only for absolute encoders the adjustment is stored in the NVRAM of the device.

For active homing you need to enable active referencing and you need to connect the limit switches to the reversal cam inputs. But how to do it can be seen in the EPOS masks for homing and in the function manual (chapter EPOS).

 Yes, we are usinh incremental encoder servoMotor.  Telegram used : PZD 111

In the homing tab in the starter we can select the limit switch as reversal cam inputs. We did that . Here is my POS_STW2 values 

POS_STW2.X9 = true;

Selected limit switches in reverse cam inputs(cu305 X130.2 and X130.5 are configured as limit switches) and command is given via STW1.X11 

Now what happens is when i engage the reverse limit , minus cam reached error is happening in drive. I also connected the same limit switch via POS_STW2.X2

In the function manual i coudnt able to find EPOS masks for homing?. Can you give me a link of the proper manual

TechTeam

Hello,

here the link to the manual:

https://support.industry.siemens.com/cs/ww/en/view/109757573

Homing is described in chapter 8.8.4.

 Hi,

But i couldn't find any information on how to use reverse limit switch as reference cam.

I have experience using referencin in using simotion . In that there is a tick mark space where we can specify that reverse limit switch can be used as reference cam.

We need similar kind of feature here. Did cu305 doesnt has this feature?. Do we need an external reference switch always for referencing?!

Hi,

Thanks. Got it