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PI controller of 6RA70 drive

Thread Starter: sparten   Started: 5/12/2012 1:39 PM   Replies: 9

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  5/12/2012, 1:39 PM
sparten
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Hi expert,
             i wanted to know about PI controller of 6RA70 drive????Rnf:lblSmileyTooltip_ think
what is excatly happen with parameter setting of  p225& p226 ?????Rnf:lblSmileyTooltip_ think
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  5/12/2012, 2:39 PM
Anchobi
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I'm not sure of what you really want to know. perhaps you can tell us what you are trying to do and what are your challenges. 

at any rate

These parameters are of course your Kp and Tn

Inside the PI controller the proportional term feeds into the integral term. 

The formula in the frequency domain looks something like 

Kp(1+TnS) / TnS

Kp works directly on the error term - so big value big response
Tn is more responsive as a shorter time. Small time = fast response. 

If either value are too responsive the system will be unstable.
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  5/16/2012, 7:17 AM
sparten
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Hi Anchobi,
                thanks for your replay...actualy i am using 6RA70dc drive for Boring machine application in which i wanted to run drive on 0.1% setpoint by port...
during this application i run drive on 0.2%,0.3% setpoint my drive running on this two setpoint well but whenever i am running my drive on 0.1% setpoint variation are very high..
.for feedback signel i am using Analog techo....
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  5/16/2012, 8:49 AM
PISCEAN 2010
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sparten wrote:
Hi Anchobi,
                ......but whenever i am running my drive on 0.1% setpoint variation are very high..
.for feedback signel i am using Analog techo....


Hello,
I don't think this vibration is related with drive.
Is this new machine or old machine?
I presume, this is old machine & drive is replaced by 6RA70. In this when you run the motor at very low RPM, please check the following.
1. First, isolate motor from load & check at 0.1% setpoint motor must rotate smoothly, withour  any jerks. If jerks are observed, 
a. Please check the motor bearings, greasing, lubrication etc.
b. Check analogue tacho individually. At low RPM its out put should be constant, smooth & linear.
2. Second check motor brush condition & rocker position. It should be perfect & properly tight.
When on no load, at 0.1% set point, motor runs smoothly, then you may couple the load & check for vibrations. If still vibrations are present then check spindle lubrication & other related mechanics.
Hope this helps you. 
Tell me and I will forget. Show me and I will remember. Involve me and I will understand. -Confucius
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  5/16/2012, 8:56 AM
KSN
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sparten wrote:
Hi Anchobi,
                thanks for your replay...actualy i am using 6RA70dc drive for Boring machine application in which i wanted to run drive on 0.1% setpoint by port...
during this application i run drive on 0.2%,0.3% setpoint my drive running on this two setpoint well but whenever i am running my drive on 0.1% setpoint variation are very high..
.for feedback signel i am using Analog techo....

Hello.
For you case use adaptation of P-gain. Look at function diagram G151 and use P550, P553, P556, P559 to decrease P-gain at lower speeds. As input signal use actual speed - K0167.
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Thank you for this post from:
PISCEAN 2010
  5/18/2012, 6:51 AM
sparten
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Hi KSN,
        thanks for your repaly i will try this tell you later....
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  5/18/2012, 6:52 AM
sparten
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Hi PISCEAN 2010,
                          thnaks for replay....
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  5/19/2012, 11:15 AM
sparten
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Hi PISCEAN, yes your are right its old machine and old analog card drive is replaced by 6RA70 drive... motor and techo are also old... i have checked in no load condition that at slow speed motor is operating smoothly...no any vibration.. .i dont know about other mechanical things that you have mention to check bcz my customer is telling me that on that old analog drive boring machine is operating well so no any problem in techo and all other things that you have mention to check.. problem creat whenever we switch to this 6RA70 drive ,,,,,



=== Edited by sparten @ 5/19/2012 11:17 AM [GMT ] ===
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  5/19/2012, 11:22 AM
KSN
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Have you tried P-gain adaptation at slow speed?
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  5/20/2012, 7:35 AM
PISCEAN 2010
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sparten schrieb:
Hi PISCEAN,
 yes your are right its old machine and old analog card drive is replaced by 6RA70 drive... motor and techo are also old... i have checked in no load condition that at slow speed motor is operating smoothly...no any vibration.. .i dont know about other mechanical things that you have mention to check bcz my customer is telling me that on that old analog drive boring machine is operating well so no any problem in techo and all other things that you have mention to check.. problem creat whenever we switch to this 6RA70 drive ,,,,,


Hello sparten,
Please check the tacho as explained in my earlier post. 6RA70 is digital drive & earlier was analoge. Technology wise there is vast difference. I know from my past exprienece, that whenever there is change in technology, such type of resistence do occur. (As your customer says, with the older drive machine was running smoothly & hence expecting the same or even better performance from the new drive.) Nothing is wrong. But for this new technology drive to perform, it also needs best quality feedbacks & inputs. So check the analogue tacho out put wave form at low RPM, check for rippls in out put waveform, also check linearity of tacho out put. Talk with technical person at customer. Explain him about the technical requirements of drive to perform. I hope, the concrened person will also agree. In most cases, I have found as over periods of utilisation, mostly analogue tacho out put is not linear, either at lower or upper speed range. May be carbon brusehes are worn out more than the limit, excessive carbon dust or commutator, dry soldering at commutator segments, uneven spring presssure, or flexible coupling problem & so on.  
Please check the value at P745 & check by increasing the same. (P745= filter time at actual analogue value)
Regards,

DEEP.

P.S. I presumed that speed, current & field optimisation tests are carried out. Moreover please reply whether you have adjusted the gain values suggested by Mr. KSN

All the best.Rnf:lblSmileyTooltip_    
Tell me and I will forget. Show me and I will remember. Involve me and I will understand. -Confucius
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