Announcement

Collapse
No announcement yet.

PF4 Locked parameters

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

    PF4 Locked parameters

    We set up a system where 2 small VFDs control separate pumps. P1 only runs with A product.
    P2 only runs with B product and neither should run when the other does. A couple years ago we noticed both pumps running. Someone, we thought, had messed with the parameters for the onboard relay which is part or our interlock. We set the parameter again and locked them. Fast forward to yesterday and we have the same problem. Everyone swears, and I believe them, that they didn’t touch. The parameter and only that one had changed,AFAIK. We had to unlock to change it back.

    Anyone with a similar problem with that drive? A solution?
    Tom
    TBLO

    #2
    I have some familiarity with programmable controllers, but not yours in particular...

    Check for any conditions that would change the settings back to as-shipped defaults. But why would that leave your lock intact?? And how would only 1 parameter in your logic be changed?

    Any possibility of the controller reverting to a previously saved version? Perhaps a power glitch makes it re-start the last saved version? Are you sure the changed parameter has been saved as part of the configuration??

    How does your interlock check the 'run' status of the other pump? Any possible glitches there? Although you said there was a changed parameter in the controller.

    Comment


      #3
      There are two potential issues, but first, are you using the Comm port for making program changes? If not, then one of the issues is not in play.

      Assuming not, the other one is that someone is changing it on purpose and lying about it.

      Unlike all of the other PowerFlex drives, the PF4/40 does not have a password protection feature. So if you set the A101 [Parameter Lock] parameter to (1) to lock it, all someone needs to do to unlock it again is to set A101 back to (0). Anyone who can download and read the manual can do that. The way to control that is to not allow access to the keypad of the drive, i.e. enclose it and put a window on the door to see the display, but not use the key pad unless you have a key to the enclosure door. I've even see people make a little hinged steel strap with a padlock hasp going over the keypad for that purpose. The other solution is to change to the PF523, it has password protection.

      If you ARE using the Comm port to make changes to the programming or send parameters from a PLC, there is potentially another issue. The default programming for the PF4 class drives is for the drive to use the EEPROM as the Non Volatile Storage (NVS) memory and the programming resides there, so the RAM memory that the drive runs from is pulled from the EEPROM every time the drive is powered up. Depending on whether this is a PF4 or 4M (the parameter numbers are different) this is changed in the [Comm Write Mode] parameter. If you make a lot of changes or the drive has power cycled a lot, this setting can exhaust the limited number of write cycles that EEPROM memory is burdened with, it's I think about 10,000 read/write cycles. If you change the [Comm Write Mode] to be to use the RAM directly, the problem is that it will lose that programming every time the power is cycled. So you would ONLY do that if you are "pushing" the drive programming down from a PLC or PC every time power is cycled. If someone changed the [Comm Write Mode] to use RAM and then disconnected the comm port, the drive reverts to Default settings every time power is lost.
      __________________________________________________ ____________________________
      Many people are shocked when they discover I am not a good electrician...

      I'm in California, ergo I am still stuck on the 2014 NEC... We'll get around to the 2017 code in around 2021.

      Comment


        #4
        Ok, small details, I know, I know....

        The PF4 we have that is changing parameters does have a remote HIM. Could there be a conflict as to what is stored in it vs the drive itself? Can someone access those parameters from there? We put it on years ago and haven't delt with another since then.

        A55 is our parameter that is changing.
        Tom
        TBLO

        Comment


          #5
          So, yes we are using the com port for speed reverence, P038.
          Tom
          TBLO

          Comment


            #6
            Originally posted by ptonsparky View Post
            Ok, small details, I know, I know....

            The PF4 we have that is changing parameters does have a remote HIM. Could there be a conflict as to what is stored in it vs the drive itself? Can someone access those parameters from there? We put it on years ago and haven't delt with another since then.

            A55 is our parameter that is changing.
            The PF4 didn't have a DSI port built-in for connecting a remote HIM, so you had to add an RS485-DSI adapter. So that meant that the remote HIM is using the Comm port and the issue I mentioned earlier may be in play.
            __________________________________________________ ____________________________
            Many people are shocked when they discover I am not a good electrician...

            I'm in California, ergo I am still stuck on the 2014 NEC... We'll get around to the 2017 code in around 2021.

            Comment


              #7
              Originally posted by Jraef View Post
              The PF4 didn't have a DSI port built-in for connecting a remote HIM, so you had to add an RS485-DSI adapter. So that meant that the remote HIM is using the Comm port and the issue I mentioned earlier may be in play.
              I deciphered that to mean there is not much I can do about it and that's good enough. Its all being replaced in some form or fashion in the next couple months which will lead to another thread on how the heck to give a price to someone that does not know what or how they want to do what they think they want done. Logic?
              Tom
              TBLO

              Comment


                #8
                What I meant is that since it’s is a remote HIM, look at the [Comm Write Mode] parameter to see it’s set to “Ram only”, because that would mean it loses its programming every time power is cycled. If it is, put it back to “EEPROM”.
                __________________________________________________ ____________________________
                Many people are shocked when they discover I am not a good electrician...

                I'm in California, ergo I am still stuck on the 2014 NEC... We'll get around to the 2017 code in around 2021.

                Comment


                  #9
                  Originally posted by Jraef View Post
                  What I meant is that since it’s is a remote HIM, look at the [Comm Write Mode] parameter to see it’s set to “Ram only”, because that would mean it loses its programming every time power is cycled. If it is, put it back to “EEPROM”.
                  I got that part, but it's cycled often enough I don't feel that's happening.
                  Tom
                  TBLO

                  Comment


                    #10
                    Originally posted by ptonsparky View Post
                    I deciphered that to mean there is not much I can do about it and that's good enough. Its all being replaced in some form or fashion in the next couple months which will lead to another thread on how the heck to give a price to someone that does not know what or how they want to do what they think they want done. Logic?
                    Hummm --
                    You just got demoted to "Engineer-of-Record". And the customer needs to have a price before they have a scope. Hopefully you have a good relationship with the customer - if not, well, "yer screwed" (using precise engineering terms - of course)

                    Maybe:
                    work up a scope for a generic.
                    price out material and labor for a PLC with sufficient I/O
                    Price out material and labor for a VFD(s)
                    Be specific about the material you are providing.
                    Be specific any changes to meet their scope changes are extras

                    And absolutely charge for your engineering. You probably can't call it "engineering" - but you will think of something to call it that you can bill for.
                    Without data you’re just another person with an opinion – Edwards Deming

                    Comment


                      #11
                      Originally posted by iceworm View Post
                      Hummm --
                      You just got demoted to "Engineer-of-Record". And the customer needs to have a price before they have a scope. Hopefully you have a good relationship with the customer - if not, well, "yer screwed" (using precise engineering terms - of course)

                      Maybe:
                      work up a scope for a generic.
                      price out material and labor for a PLC with sufficient I/O
                      Price out material and labor for a VFD(s)
                      Be specific about the material you are providing.
                      Be specific any changes to meet their scope changes are extras

                      And absolutely charge for your engineering. You probably can't call it "engineering" - but you will think of something to call it that you can bill for.
                      I don’t care too much. They are hard to work with. Not too many PLC guys in the vicinity and they can use the experience if they want this one. I’m old.

                      Eta: They were discussing where and if they would have electric slide gates and how they would be operated. That was tabled for further discussion and in the next breath they wanted a price worked up for the whole project. How many motors do they have? That’s a question for you, because they couldn’t answer it.
                      Last edited by ptonsparky; 04-26-19, 03:30 PM.
                      Tom
                      TBLO

                      Comment


                        #12
                        Kind of reminds me of the old architectural spec for a house as written by a business consultant (I can't remember the whole thing)- the house is to have between 3 and 25 rooms on at least two floors (to be determined), plan and equip for a future basement, any exterior color is acceptable but my wife likes blue..... etc

                        Comment


                          #13
                          Originally posted by ptonsparky View Post
                          Its all being replaced in some form or fashion in the next couple months which will lead to another thread on how the heck to give a price to someone that does not know what or how they want to do what they think they want done. Logic?
                          part of the art of being a consultant is extracting what a customer actually wants from what they are telling you. the tree swing cartoon comes to mind. the worst is when you give them what they describe and it gets installed that way. they call you and say, "this isn't what i wanted."

                          looking forward to that thread

                          Comment


                            #14
                            Originally posted by drktmplr12 View Post
                            part of the art of being a consultant is extracting what a customer actually wants from what they are telling you. the tree swing cartoon comes to mind. the worst is when you give them what they describe and it gets installed that way. they call you and say, "this isn't what i wanted."

                            looking forward to that thread
                            My SIL asked me about that project. As I told him I suspect that CEO will bend himself over backwards before calling back. He didn't like the number of zeros on my WAG.
                            Tom
                            TBLO

                            Comment

                            Working...
                            X