You are not registered yet. Please click here to register!


 
 
plc storereviewsdownloads
This board is for PLC Related Q&A ONLY. Please DON'T use it for advertising, etc.
 
Try our online PLC Simulator- FREE.  Click here now to try it.

---------->>>>>Get FREE PLC Programming Tips

New Here? Please read this important info!!!


Go Back   PLCS.net - Interactive Q & A > PLCS.net - Interactive Q & A > LIVE PLC Questions And Answers

PLC training tools sale

Reply
 
Thread Tools Display Modes
Old December 6th, 2017, 07:10 AM   #1
qsubhani
Member
Canada

qsubhani is offline
 
Join Date: Jan 2014
Location: Markham
Posts: 13
PowerFlex 700

I am having a problem to find out the cause of dropping our power flex 700 series drive. We had an issue a month ago that drive burnt out and we were replaced with new drive.
Using the old cassette from old drive, HIM module and Controlnet Card, we were able to run the drive. As well as I verified all the parameters that we have it found all ok.
Problem:
From last two weeks we noticed that drive drops to 20 %(12HZ) and back to normal by itself .
This drive only has a provision to RUN from BAS (Building Automation System) and it's running on
Controlnet Network.
Following is the Rung for starting of AH unit.


Speed Reference Parameters:
Parameter# 90= DPI Port 1 value=18
Parameter# 91= DPI Port 5 value=22
Parameter# 100= 100
Parameter# 101= 5.0
Parameter# 102= 10.0
Parameter# 103= 20.0
Parameter# 104= 30.0
Parameter# 105= 40.0
Parameter# 106= 50.0
Parameter# 107= 60.0
Process PI:
Parameter# 126 = Set Point value =0
Parameter# 128 = Analog IN 2 value =2

Please advise how to trouble shoot.
  Reply With Quote
Old December 6th, 2017, 10:07 AM   #2
Ken Roach
Lifetime Supporting Member + Moderator
United States

Ken Roach is offline
 
Ken Roach's Avatar
 
Join Date: Apr 2002
Location: Seattle, WA
Posts: 13,909
Welcome to the PLCTalk forum community !

How long does the drive remain at 12 Hz ? What sort of load is it driving, and are there any physical changes to the load ?

Have you put in a logic trap to be sure that the Reference value is not actually changing ?

Is the low frequency exactly 12 Hz, or is that an approximate number ? 12 Hz isn't one of the Preset or Minimum frequency values, so it has to be coming from some other function of the drive, or you're only seeing it at some point while the drive is decelerating or accelerating past that value.

There are parameters that will allow you to monitor the source of the Command.

DPI Logic Result (Parameter 271) will show you which devices are telling the drive to choose a reference.

Reference Owner (Parameter 292) will show you which device is actually giving the reference to the drive.

I've seen drives "randomly" switch to a Preset Speed when there is electrical noise present and unused wires connected to the Digital Inputs. I set my Digital Inputs to "no function" to prevent this, and/or jumper them to DC Common to keep them False.
  Reply With Quote
Old December 6th, 2017, 01:17 PM   #3
Lovell
Member
Canada

Lovell is offline
 
Lovell's Avatar
 
Join Date: Feb 2013
Location: Saskatchewan
Posts: 67
Check your IO card and see if anything is wired to Digital In 4.

If so check P364 - default value is Speed Sel1. If P364 is '15' Speed Sel 1 then speed will change if Digital In 4 is true. You can change it to 0 (not used) if you don't want this action.
  Reply With Quote
Old December 7th, 2017, 07:00 AM   #4
qsubhani
Member
Canada

qsubhani is offline
 
Join Date: Jan 2014
Location: Markham
Posts: 13
Hi Loveall,
My Digital Input 4 are not in used and value is set to 0
  Reply With Quote
Old December 7th, 2017, 02:20 PM   #5
Lovell
Member
Canada

Lovell is offline
 
Lovell's Avatar
 
Join Date: Feb 2013
Location: Saskatchewan
Posts: 67
It looks like Parameter 365 may be the source of your problem. If something is wired to Digital In 5 then speed would change when that input is true. You can set P365 to 0 as a test to see if that solves the problem.
  Reply With Quote
Old December 7th, 2017, 02:47 PM   #6
Lovell
Member
Canada

Lovell is offline
 
Lovell's Avatar
 
Join Date: Feb 2013
Location: Saskatchewan
Posts: 67
You can also change P102 to 60Hz. It is likely set at 10Hz and that would be the command it would get (if Dig In 5 was true) but would not go below 12Hz if that is your minimum speed setting.
  Reply With Quote
Old December 7th, 2017, 04:14 PM   #7
qsubhani
Member
Canada

qsubhani is offline
 
Join Date: Jan 2014
Location: Markham
Posts: 13
I am a bit confused that when my motor runs on network through DPI port 5 where it gets the speed signal.
My understanding that when runs on DPI port 5 (Parameter# 93 = 22)motor gets the control command and goes to Preset speed 1 selection and if I need to control from terminal blocks than I need preset speed selection 1 to 7(parameter#101 to 107)
  Reply With Quote
Old December 8th, 2017, 08:32 AM   #8
Lovell
Member
Canada

Lovell is offline
 
Lovell's Avatar
 
Join Date: Feb 2013
Location: Saskatchewan
Posts: 67
From your settings:
Parameter# 90= DPI Port 1 value=18
Parameter# 91= DPI Port 5 value=22

Your speed reference is coming from the local HIM. (DPI port 1)
and oddly, your ControlNet is adjusting the maximum speed for an analog speed command input.

Did you try my suggestions? What is the result?
  Reply With Quote
Old December 8th, 2017, 09:50 AM   #9
qsubhani
Member
Canada

qsubhani is offline
 
Join Date: Jan 2014
Location: Markham
Posts: 13
I didn't get an approval from production to do any changes. Last night we put back to Auto from BAS and so far NO dropping speed.
We have an upcoming shutdown during Christmas and at that time we will do all tests.
  Reply With Quote
Old December 7th, 2017, 06:44 AM   #10
qsubhani
Member
Canada

qsubhani is offline
 
Join Date: Jan 2014
Location: Markham
Posts: 13
Hi Ken,
Thanks for your reply. I am trying to provide maximum information that you are requested.
How long does the drive remain at 12 Hz ? What sort of load is it driving, and are there any physical changes to the load ?
I checked with trend and speed drops almost 3 minutes and goes back to normal. Bear in mind that we put the speed on manual mode from BAS and still drops to 12HZ(minimum speed).There is no such load changes but I verified from field that actually motor goes to minimum speed .
Have you put in a logic trap to be sure that the Reference value is not actually changing?
I didn't get your point for logic trap. I don't have access to go online and checked the program but I can request the concerned department for specific point of trouble shooting.

Is the low frequency exactly 12 Hz, or is that an approximate number? 12 Hz isn't one of the Preset or Minimum frequency values, so it has to be coming from some other function of the drive, or you're only seeing it at some point while the drive is decelerating or accelerating past that value.
Yes I verified from field that speed goes to 12HZ (minimum speed )parameter#81 set at 12HZ and 12HZ is =20% of our BAS scale(0 to 100%)

There are parameters that will allow you to monitor the source of the Command.
We are using DPI port5 (connected on controlnet) for speed reference. I checked speed reference and parameter
Parameter# 90= DPI Port 1 value=18
Parameter# 91= DPI Port 5 value=22


DPI Logic Result (Parameter 271) will show you which devices are telling the drive to choose a reference.
Parameter# 91= DPI Port 5 value=22



Reference Owner (Parameter 292) will show you which device is actually giving the reference to the drive.
Reference Owner Parameter set= 1(Digital Input 1)

I've seen drives "randomly" switch to a Preset Speed when there is electrical noise present and unused wires connected to the Digital Inputs. I set my Digital Inputs to "no function" to prevent this, and/or jumper them to DC Common to keep them False.
My Digital Inputs are
Parameter# 361= 4(STOP)
Parameter#362=15(Speed Select1)
Parameter#363=18(Auto/Manual)
Parameter#364=0(Not Used)
Parameter#364=0(Not Used)
Parameter#365=16(Speed Select2)
Parameter#366=1(Enable)
  Reply With Quote
Old December 6th, 2017, 06:45 PM   #11
jraef
Member
United States

jraef is offline
 
jraef's Avatar
 
Join Date: May 2006
Location: Northern California
Posts: 1,479
If all of that fails, when it is doing this, check the value of Parameter 210, bit 10 to see if the drive is going into Current Limit. Current Limit will override your speed command in an attempt to keep the current under control. If it is going into Current Limit and dropping the speed to 12Hz, next check the settings of parameter 148 and 147. Someone may have inadvertently set the CL to a really low value, not understanding what it means. The factory default setting is the Drive's maximum current setting, 150%. If the motor current is trying to jump to over 150% while the machine is running, something is wrong with your load, such as something jamming. Given that the previous drive burned itself out, that problem may have been what cause it and still exists.

Last edited by jraef; December 6th, 2017 at 06:48 PM.
  Reply With Quote
Old December 7th, 2017, 07:18 AM   #12
qsubhani
Member
Canada

qsubhani is offline
 
Join Date: Jan 2014
Location: Markham
Posts: 13
Hi Jraef,
I didn't get a chance to check the drive status bits because it happens for a while and goes back to normal. Anyway I verified at normal running that BIT 0(ready),1(Active),2(Running)and 13(DPI at 500K) are active .
Parameter # 147 is set= 0 and we are not using this current limit option.
For my understanding when load sudden change it has to trigger first Motor overload.
My Motor control parameters are
Parameter#40=Induction
Parameter#41=575.0 VAC
Parameter#42=15.3 Amps
Parameter#43=60.0 HZ
Parameter#44=1780 RPM
Parameter#45=15.00 HP
Parameter# 46=0 Horsepower
Parameter# 47=20HZ
During running condition motor runs @44.8HZ and taking current 8.8A
  Reply With Quote
Old December 7th, 2017, 09:11 AM   #13
osmanmom
Member
Malaysia

osmanmom is offline
 
Join Date: Mar 2014
Location: JOHOR
Posts: 1,414
i not familiar this vfd just rough read from manual

i guess it normal behavior because this is PI mode
  Reply With Quote
Old December 7th, 2017, 09:19 AM   #14
jraef
Member
United States

jraef is offline
 
jraef's Avatar
 
Join Date: May 2006
Location: Northern California
Posts: 1,479
With 12Hz being your minimum speed setting, I'd guess then that the drive is losing its speed reference command and dropping to the minimum speed, because you have it programmed that way. I no longer have my manual with me, but there is a parameter someplace where you tell the drive what to do on a loss of communications. One option is "Run at Minumum", another is "Maintain Previous Speed Command", and I think it offers a "Fault and Shut Down" option. If Run at Minimum is what you want, then you need to find out why you are dropping out your COMM signal.
  Reply With Quote
Old December 7th, 2017, 09:59 AM   #15
qsubhani
Member
Canada

qsubhani is offline
 
Join Date: Jan 2014
Location: Markham
Posts: 13
Hi Jraef,
I checked the parameters under communication module and cant find the parameters that says what to do under loss of communication.
I believe that
If the drive can't talk to the 20-Comm-D over DPI, it gives a DPI comms fault and an "8x" error code.

If the drive can talk to the 20-COMM-D but the 20-COMM-D can't talk over Device Net to the scanner, the drive faults on a Network communication fault and gives an "7x" error code.

Is there any way I can find that problem is in our hardware(Only one selector switch of AUTO/MANUAL)installed on local drive panel.That gives the signal to drive that I am on Auto and drive than can RUN through control net.
How I can be make sure that NO loss of communication occurred when motor goes to minimum speed.
  Reply With Quote
Reply
Jump to Live PLC Question and Answer Forum

Bookmarks


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Topics
Thread Thread Starter Forum Replies Last Post
1336-WB035 Braking Chopper on a Powerflex 700 VC Jasondelane LIVE PLC Questions And Answers 4 December 14th, 2015 11:05 AM
Migrating from 1336 to Powerflex 700 on PLC5 system Jasondelane LIVE PLC Questions And Answers 2 December 8th, 2015 03:45 PM
PLC5 Powerflex 700 ddsiller LIVE PLC Questions And Answers 2 November 19th, 2015 02:06 PM
Powerflex 700 & rslogix 5000 edwardeduful LIVE PLC Questions And Answers 35 March 23rd, 2015 03:10 PM
Powerflex 700 Need Help Sean Wing LIVE PLC Questions And Answers 8 August 4th, 2011 10:24 PM


All times are GMT -5. The time now is 08:20 PM.


.