Gary Burton

Iam getting registration time not position with the GSV Read the 3 instructions again...I don't want the slave position (A1)

Hi TWC - Iam using a MAR to arm the input and the registration also sets off an event task...which is where the GSV SSV GSV are located. It all works perfectly ....except for the noise The time it takes for a GSV etc is not relevant because the interpolated position is used later in a cam....the cam starts after an offset.....

Here is what the GSV SSV GSV looks like....A3 is my master and A1 is the axis that the registration input is wired to (the kinetix drive is A1) GSV(AXIS,A1,Registration1Time,A1RegTime) SSV(AXIS,A3,InterpolationTime,A1RegTime) GSV(AXIS,A3,InterpolatedActualPosition,A3PosWhenA1Registered) I guess I should have posted this code at the beginning......This is how I think I get the position of my master....and I think it is correct. What do you think TWC?

Ah yes..... if only life was that simple. The system is working, I replaced a Delta Tau SMCC with this AB Kinetix system.....I am just trying to learn more about motion control as this was my first project. Right now I'm using gearing because my camming did not work due to noise. The tolerance that the machine is currently getting is within our spec.... Thanks for your contribution

TW- basically what is going on is that when I try to cam to my master using the GSV SSV instructions to find the position of the master when the slave registered, the position that the master is reporting is bogus....because of noise......so its basically what Peter is saying, you cannot get accurate positioning untill you have reliable position information from the device you are camming or gearing to. I have to get a more accurate encoder input from my master axis.....its is noisy due to mechanical vibration, jerking etc My encoder is 5000 ppr which results in a resolution of 0.00125 pulses / .001".....it used to be .0025 pulses / .001" I guess I did not go high enough on the encoder counts / rev. in hindsight

So I understand quantizing as the "smoothing" of the encoder inputs to make a nice "smooth" signal...how far off am I? Firing the manager is not an option

Peter - any more thoughts on this?

How about this? http://www.cognitoquam.gr/en/tm/encdrf_b.html ...a little spendy though I'm using kinetix.....the noise is about 10 % Thanks for your answers

I have a generic question regarding the coarse update time. If I have an event task that is triggered by an axis registration input I have a possible delay of (coarse update time+ SERCOS ring update time)....in my case this could be anywhere from a best case scanario of about .1 milliseconds to about 2.5 milliseconds. Is there a way to make the motion group start its update off a trigger....?

Unreal, the Boks won

That is my next move - the encoder will be here Tuesday.....the advanced filter option sounds interesting will make for a good read - how would you filter it if not in the PLC?

Peter - thanks for taking the time to answer my questions... On the noise, I have tried every concievable way to eliminate it - changed encoders, seperate shielded beldin run completely away from other cables etc etc...it remains. So back to mechanical noise. The drive is a eurodrive variable speed....variable shiv. It is rough in operation, vibration is present.....could this be it? The encoder is driven by a cogged belt and geared down... I don't know enough about this to make a judgement call on the mechanical side (Millwrights don't like to be told things like this)

Time = distance

My master is an auxilliary feedback...so no control. Is it possible to use a non axis tag to cam or gear to? Maybe build some filtering through ladder and gear to that? Or maybe it will make the problem worse....

Iam afraid you are right...they should walk it

Well I can't get rid of it.... I was just hoping there was some other way to trigger the motion group execution instead of by the coarse update period....... I was aware of how to get the registration position.. Thanks for your help

Boks to win today Gerry ;)

Yes time can be used to set interpolated time on another axis and then get position of that axis......for camming for example

Yes TWC....that is what the registration does as well, that is store the position on registration

Well it was mostly a question out of curiosity....I was wondering if there was a way to trigger the motion group scan...or switch it off.. I know how to capture the position at registration using GSV and SSV..and then use that for interpolation (used a cam profile) I just like playing with different scanerios One question I do have is when the registration occurs, the position value of the axis used is stored (so it can be retrieved with a GSV).......how long does this information stay in the drive? Until you re-arm the registration input and the input goes high again? I'm still unsure exactly how the registration data is stored and reported.... Thanks for replying to my question.

Well the event is triggered by the registration input....which is located on the drive. The sercos ring update time is .5 m/s.....and the coarse update time for the motion group is 2 m/s. So if the drive sees an input, it could concievably take .5 m/s to reach the plc and then if it catches the motion group on the front end of the coarse update time it will have to wait till the motion group completes its scan before executing the event task......This is assuming the motion group executes with priority 1 every coarse update time. The motion group and the plc scan are not asynchronous right? Does this make my question any clearer?

Another CL Motion with Kinetix question: When a registration occurs is the position registered in the drive or in the CL data table? ie does the drive store the position or is it merely reported back to the PLC?

\ Hmmmm.....I guess not

SLC 500 family has a stepper module......

I just completed a project that used kinetix 6000 drives and sercos...MO3SE card. It was very easy to setup and configure and I have experienced zero problems with drive faults other than program induced, by me I'm impressed although I do not have a lot of motion experience. I used camming and have achieved .0005" tolerance on a system travelling at around 10"/second, this was sufficient for my application.