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Secondary Encoder G-Code - 840D SL

Created by: aex at: 7/24/2013 4:03 PM (13 Replies)

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7/24/2013 4:03 PM	Rate (0)
aex Posts: 17 Rating: (0)	Hey, So I'm trying to use the dual port RAM to pass values back and forth between the PLC and the NC. I wish to pass the NCVar measPos2 back to the PLC using g-codes. I know for the first encoder it's $I_IM[axis] but I can't seem to find it for the secondary encoder. On a side note, I can't configure the scales on the drive. The scales are connected to SMC20's and those are connected via Drive-Clique to the NC. When the devices are plugged in there is no detection via the NC. I'm in a bit of a pinch so any help is seriously appreciated! Regards, aex
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7/24/2013 4:29 PM	Rate (1)
CNC600 Silver Member Joined: 10/27/2009 Last visit: 3/15/2024 Posts: 455 Rating: (77)	Hi, measPos1 & measPos2 deliver the ENC-values, separated for each Encoder. $A_IM & &A_IW deliver the position values related to the MCS resp. WCS - based on the active encoder (PLC-Interface signal). The important difference in between of measPosX and $A_IM is: ==>measPosX does NOT include any compensation values (EncComp, CACcomp, TempComp...), it's only the ENC-Position. I dont know what kind of special and secret application You want to create - but reading axes positions via PLC (cyclic???) looks not really professional...
	hope that helps CNC600
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7/25/2013 3:39 PM	Rate (0)
aex Posts: 17 Rating: (0)	Essentially I'm trying to read the inner diameter of a cylinder with 114 nodes inside of it. Is there an $VA_IM for the second encoder? I know that $VA_IM[A] for example will read only the first encoder. I can see the value of the second encoder in diagnosis -> service axes, but not sure how to obtain that in the nc.
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7/25/2013 5:06 PM	Rate (1)
CNC600 Silver Member Joined: 10/27/2009 Last visit: 3/15/2024 Posts: 455 Rating: (77)	You should get the Encoder specific values by $VA_IM1[MachAx] for ENC1 and $VA_IM2[MachAx] for ENC2 perhaps You should read these values by SYNACT (put the values in an Array anywhere) instead to transfer the values in real time into the PLC.
	hope that helps CNC600
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7/25/2013 8:50 PM	Rate (0)
aex Posts: 17 Rating: (0)	How do I do it that way? Another alternative is to write to a text file via the NC rather than doing the logging in WinCC. Could I perhaps have an example of that? Regards, aex
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7/25/2013 9:34 PM	Rate (1)
CNC600 Silver Member Joined: 10/27/2009 Last visit: 3/15/2024 Posts: 455 Rating: (77)	Wrinting a file is also possible by NC-program. ==> see WRITE-instruction. by SYNACT: G0 X-10 ; positioning X-Axis before Trigger ; start SYNACT ID=2 EVERY ($AA_IM[X] > $R[0] * 2) DO $R[100+$R[0]]=$VA_IM2[Z] $R[0]=$R[0] + 1 G1 X100 F100 ; movement X-axis M2 The SYNACTdo: Checking X-Position, alwaya when Position = 2*n execute: Z-axis Position to R100+ increasing factor (+1) finally I expect the Z-values stored in R100, R101... (the sample is not tested, but should be run...) In a final application I'd replace the R-Parameter by other synact-specific variables to get a more professional designed program... The System executes the defined SYNACT each IPO-cycle. You cannot get the same frequency with WINCC or PLC-FB2-actions!
	hope that helps CNC600
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7/26/2013 3:03 PM	Rate (0)
aex Posts: 17 Rating: (0)	Could you explain this block in written description too? I can't seem to figure out exactly what's going on with the ID=2 and the X-axis closed loop set point. CNC600 ; start SYNACT ID=2 EVERY ($AA_IM[X] > $R[0] * 2) DO $R[100+$R[0]]=$VA_IM2[Z] $R[0]=$R[0] + 1 M2 Also is there a command that will let me re-zero an encoder through G-code?
aex Posts: 17 Rating: (0)
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7/26/2013 5:00 PM	Rate (1)
CNC600 Silver Member Joined: 10/27/2009 Last visit: 3/15/2024 Posts: 455 Rating: (77)	please refer to the documentation, function Manual for SYNACTs: http://support.automation.siemens.com/WW/view/en/74607173 basically: ID=x ==> user defined number of synact, 1..255, if more than one SYNACT are active: Operation is orderedin ascend numbers EVERY ==> execution always, when condition deliveres an FALSE=>TRUE-slope $A_IMx > value==> condition check (in the sample: every 2mm) DO ==> separates condition and instruction $R[0] = $R[0] + 1 ==>instruction(s) for execution the previously shown SYNACT should read the Z-axis Position every 2mm of X-axis movement into the R-parametrer-area. As I know there is no command to reset a single Encoder. But You can preset an axis by command PRESETON in SYNACT: EVERY condition DO PRESETON[X,0) ; fullfilled condition sets X-axis to "0"
	hope that helps CNC600
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7/26/2013 5:34 PM	Rate (0)
aex Posts: 17 Rating: (0)	For the secondary encoder, it would beDO PRESETON[X2,0)? Thank you so much for the help, you've been amazing! Regards, aex
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7/26/2013 5:52 PM	Rate (1)
CNC600 Silver Member Joined: 10/27/2009 Last visit: 3/15/2024 Posts: 455 Rating: (77)	No. The PRESETON is not related to an encoder. You just modify the MCS-value without touching the referenced positions ==> but the reference position atself becomes invalid. Your 2nd encoder (we're talking about it) does not belong to the axis mechqanically, You just use the data channel to transfer the encoder siganls into the CNC, right? In tis case You can move the encoder (probe?) to a reference position and store the detected MeasPos2. In Your calculation You can use this stored value to find out the differences. (I'm not sure to understand Your application)
	hope that helps CNC600
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