Skip to Content

Register Login

Industry Online Support

Technical Forum

Navigation

PQW

Created by: ICBM at: 4/25/2008 2:23 AM (16 Replies)

Rating (0)

Thanks 0

Result pages:: |; 1 | 2; |

17 Entries

Entries per page: 10 | all

4/25/2008 2:23 AM	Rate (0)
ICBM Posts: 7 Rating: (0)	Hi I am new to the siemens PLC so I hope this makes sense We have S7 317 PLC. our remote I/Os are all wagos. Also we are using AstromVFDs to control our motors and all is linked through the profibus. My Problem is, wesupplyArpm and a Torque output from a remote wago AO for a third party to monitor. This was modified so the A/O module beside it supplied the the same outputs to anotherthird party contractor (these are all 4-20mA) We shut down and moved (I am on aoil gas/oil drilling rig). Since the move we have lost the outputs fromthe modification. In the hardware configuration the outputs show up as PQWs (in this case PQW 292 and PQW 294) I cannot work out how to find the inputs these outputs are picking up,I looked in the memory blocks to find these addresses and Icant locate where they are from. Are they just transfered from the drives to the outputs as there is nomemory blocks for peripherals? I just need to know how the work my way back from the outputs to the source. I asume there must be a DB / FB to get this informtion around. How are peripheral I/Os different from the others?
ICBM Posts: 7 Rating: (0)
Suggestion To thank Quote Answer

4/25/2008 5:17 AM	Rate (0)
Phantom75 Posts: 2661 Rating: (279)	You can trace the block where the PQW is being assigned by invoking the reference data. Open any block (LAD/STL/FBD Editor) and click on Options and then Reference Data. See attached screenshot. All the best. Attachment Dokument1.pdf (548 Downloads)
Phantom75 Posts: 2661 Rating: (279)
Suggestion To thank Quote Answer

4/25/2008 11:55 AM	Rate (0)
ICBM Posts: 7 Rating: (0)	Thank you,I can now find the PQWs I can see the PQW with the cross reference but the paticular ones I am looking for are not there, PQW 292 and PQW 294. Thinking maybe that is why its not working I went looking for the PQWs in the AO that is working beside it and the 2 PQWs for this one are not showing either(PQW 276 and PQW 278). So I have PQW 276 and PQW 278 on slot 5 on the remote I/O working but they are not showing up on the the cross reference table as well as the faulty ones, PQW 292 and PQW 294? I have about 60 PIWs and PQW on the table but just not the ones I am looking for. Some of ourprogram is blocked from making changes just in case it is relavent but cant imagine that. I uploaded the program again from the PLC to my PC and double checked it with the hardware configuration butits the same. Anyideas?iget the feeling I am overlooking something fairly basic
ICBM Posts: 7 Rating: (0)
Suggestion To thank Quote Answer

4/25/2008 11:57 AM	Rate (0)
ramiv Posts: 55 Rating: (1)	Also it is possible that the outputs are written with indirect adressing, so that for example some variable contains the adress you are writing to. This could be done at a parameter to a FC call. This does not show at the cross reference listing. Here is one possibility how it can be done: L P#256.0 // pointer adress to 256 LAR1 // move adress to adress register #1 // Something other can be done here.. L 0 // # to be transferred to the output T PAW [AR1,P#0.0] // actual write to PAW, adress at AR1, no index addition But it can be done with several other ways too.. With peripheral IO the inputs are read directly from the input at the moment of the instruction, and for the outputs it is the same. With normal IO-s the I-process image is read before OB1 and Q-s written after OB1 has been run. PAW = PQW, i prefer to use German mnemonics.
ramiv Posts: 55 Rating: (1)	Last edited by: ramiv at: 4/25/2008 11:59 AM
Suggestion To thank Quote Answer

4/25/2008 12:02 PM	Rate (0)
ramiv Posts: 55 Rating: (1)	You can try to make 'reference data'-'generate', and then choose 'regenerate', it sometimes misses some of the information if there has been a lot of changes to the original project.
ramiv Posts: 55 Rating: (1)
Suggestion To thank Quote Answer

4/25/2008 6:47 PM	Rate (0)
Abdelaal Posts: 76 Rating: (16)	DEAR ICBM , I didn't get your point totally but,You have said that that you checked your hardware config. again ,check your devices one after another with monitor-modify that is done from hardware config. window to check their input and output words ,double words , etc. if these PID you are taking about not assigned to a device you can reset that again, but please do that with a copy of your uploaded program,i.e without downloading anything to plc .i hope one of the experts may give us a solution to that. I hope this helps Regards
Abdelaal Posts: 76 Rating: (16)
Suggestion To thank Quote Answer

4/26/2008 7:20 AM	Rate (0)
Phantom75 Posts: 2661 Rating: (279)	ICBM: First you should try the reference data regenerate as suggested by ramiv. If you still do not see PWQ 292/294, please open a variable table (VAT) andcheck if you see some values for PQW292/294. If you see values that are changing, it means the program is writing to the periphery outputs. You can also try forcing these outputs and if you are able to force, it means these PQW's are not being written to by the program. In short your program is not complete. Actually I tend to agree with Abdelaal: Idid notunderstand you problem completely. All the best, Phantom PS: It is possible that these analog outputs are being written to using indirect addressing as suggested before but I feel that is highly unlikely.
Phantom75 Posts: 2661 Rating: (279)
Suggestion To thank Quote Answer

4/26/2008 11:20 AM	Rate (0)
ICBM Posts: 7 Rating: (0)	Hi Hope I can explain it a little better.Wehave a remote rack with aAOdevice set up to provide asignal representing the RPMs and Torque for one of our drive motors, thisis just for ato a third party contractor to monitor us. The AOdevicebeside this was origionally a spare but was set up to provide the same outputs for yet another third party to use. This worked as well until we shut down and started up again butthis one has not worked since we have started up again. Iknow the output addresses for bothDevices and there both PQWs but cannot find either of them in the cross reference table. I have trieda data referenceregenerate but still nothing. A point if it helps is we dont have any sensors going to inputs as such fortheRPMS and Torque,the information is derived from theVariable Speed Drive which is connected through theProfibus. I just cannot work out how to track this output back to its source address. I have made a variable table with theseoutputsbut without remebering exactly what is says it tells me these point are not monitorable I checked the 2 modules with monitor-modifyin thehardware config. windowand get the same type ofmessage saying they are not monitorable. Maybethe analog outputs are being written to using indirect addressing. It may be a bit out of my league this thanks all
ICBM Posts: 7 Rating: (0)
Suggestion To thank Quote Answer

4/26/2008 1:55 PM	Rate (0)
Aret Posts: 2348 Rating: (264)	First of all you should ensure, that value on PQWs are changing. You can measure current/voltage on these outputs^) If no change dtected - It's look like that after power reset something in your programm erased :^( If it chages - that means something writes these outputs. It may be PLC, or OP or something else. >>Maybe the analog outputs are being written to using indirect addressing. It may be a bit out of my league this in this case make so - generate source for all blocks (File->Generate source) then look for "[" character. You can find all indirect addressing in this manner.
Aret Posts: 2348 Rating: (264)	Last edited by: Aret at: 4/26/2008 1:59 PM
Suggestion To thank Quote Answer

4/27/2008 5:12 AM	Rate (0)
Phantom75 Posts: 2661 Rating: (279)	ICBM: The mystery deepens... Is it possible for you to post your uploaded project? Regards, Phantom
Phantom75 Posts: 2661 Rating: (279)
Suggestion To thank Quote Answer

|

Share this page:

Share this page on...

Follow us on