ElectronGuru

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  2. Posted

    Rotate and Inertia tunes provide better results than Static, regardless of operating mode.

    https://literature.rockwellautomation.com/idc/groups/literature/documents/at/drives-at004_-en-p.pdf

    Page 36:  Auto Tune The Auto Tune test is used to identify the correct motor flux and stator electrical properties, including:

    • IR volt drop, which is voltage drop over resistance.
    • Ixo volt drop, which is voltage drop over inductance.
    • Flux current (estimated in Static Tune and measured during Rotate Tune test).
    • Slip RPM, which is calculated from motor nameplate data. If an encoder is used, the Slip RPM becomes a measured value using the encoder.

    Page 37:   Static Tune This test is used when the motor is connected to a high friction load and cannot easily be uncoupled from the motor, or when the load cannot be rotated due to mechanical constraints or a limited range of movement. The Static Tune test does not generate any motor movement. The Static Tune test results may not be as accurate as the Rotate Tune test.

    Rotate Tune This test is used when the motor is not coupled to the load, or the load is low friction. Rotate Tune is used to better identify motor flux and stator electrical properties, which are used to automatically tune the torque/current loop. The Rotate Tune test causes motor rotation at different speeds while it is executing.

    Inertia Auto Tune Test This test measures the total system inertia ( Jt). When using Load Observer, this test is executed with the load disconnected from the motor so that only motor inertia is measured. Otherwise, this test is executed with the load connected to the motor so that motor + load inertia is measured. During the test, the drive/motor is accelerated using the entered ‘Autotune Torque’ value. The time required to accelerate the motor and load from zero speed to rated speed is measured. The value of Total Inertia ( Jt) is determined from this measurement and the value of Par 9 [Total Inertia] is updated to reflect this measurement. The Par 9 [Total Inertia] value is used for a number of internally calculated parameters for the Speed Regulator. These relationships are described in Chapter 3.

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  3. Posted

    Autotune on the PF755 works as follows:

    • ROTATE - For my money this is the best tune. It rotates the motor, but the motor must not be coupled to anything.
    • INERTIA - Rotates the motor while it's coupled to a load, such as an integral gearbox or pump that can't be uncoupled.
    • STATIC - If for any reason the motor can not be rotated at all, but can be energized, Static does the job.

    So, Static=Good, Inertial=Better, Rotate=Best. 

    I don't know enough about your process to advise on the best way to get around the sometimes-master/sometimes-standalone drive situation. One possible solution could be to write code to change the drive to standalone, IF the affected parameters can be data-linked. 

  4. Posted

    @pcmccartney1 I'm trying to work on a V10 project with HMI tag alarms, whose functions are not available in V12, so I need a working V10. Not to belabor the point, but when I "downgraded" to V10 I could open a project and everything looked good until I opened any display. Then it crashed. 

    Now that I've re-installed V12, I can upgrade any existing project to V12 (sans HMI tag alarms) and things look ok on the surface, but I'm slowly finding other bugs. Things like the Runtime Security won't open in a newly created project, or FT Studio refuses to open any previously existing SE projects, even when restored from a .apa file. I would normally suspect Windows and my laptop, but I have a co-worker who has simultaneously gone through the same up- and downgrades for the same reasons I am, and he's experiencing very similar issues (though not as bad as mine) with his laptop. That leads me to believe this has to be a Rockwell FT Studio thing. 

    I think it's going to be another late night trying to figure this out but still open for any suggestions here. 

  5. Posted

    @Joe E.That's what I'm running into. There's a knowledge base topic that covers this but it's for V6. And I'm in a situation where the company manages the VMs on my company-owned laptop, so your fix is somewhere between impractical and impossible. (Damned IT people, lol). 

    Out of frustration I decided to re-install V12. ME is fine but SE refuses to open any project that I haven't created brand new. All existing SE projects or those newly restored from .apa files opens FT SE Studio, but the project explorer window is blank. No server, no display files, no FactoryTalk Linx, no nothin'! I'm out of answers and have just started clicking and right-clicking any and every random thing trying to find ANYthing that will at least get me back to where I started. 

    I've reached out to a couple Rockwell developers (Rockwell employees who (among other things) write training curriculum) and waiting to see if they have a solution. If someone else has any ideas, please!, let's hear them. If I find the solution I'll be sure to post it.

  6. Posted

    I had FactoryTalk ME and SE Studio V12 on my Windows 10 machine. A few days ago I needed to use to V10 for some alarm functions and because FT will not let you have multiple versions on one laptop, I had to downgrade to V10. Everything had been working fine until the uninstall of V12 and the install of V10. Whether in ME or SE, and even in a newly created project, opening any display crashes Studio. I have attempted two clean installs and can't seem to get it fixed. It feels more like a Windows OS issue but we're a bit stumped. Anyone else run into this?

  7. Posted

    There are some rare occasions when an old PV6 wont be able to interact with an L8 running V32 or V33. This is why I suggested double-checking product compatibility earlier. 

    Since you upgraded your firmware (and if you haven't already) you might try deleting are re-configuring your Design and Runtime shortcut paths in the communications setup. Also, I always like to test at least one or two displays from the FT Studio to make sure that the path is valid before I create the .mer. 

    If you've done all that, the next time you open the transfer tool, click on the Ethernet network icon and let the three boxes blink for at least ten or fifteen seconds. This will give Linx time to eliminate anything that it previously detected that it might not actually see at the moment. Many times I've clicked on the node too fast after opening the tool, only to find the node isn't actually where Linx can see it. This can be caused by anything from bad configurations to, an unplugged network cable, or (most embarrassingly) the power to the node being turned off.

  10. Posted

    You were informed correctly; the PF400 is primarily designed for pumps and fans. There is no PF725 that I'm aware of. I think you might have meant to type 755. There is a PF525 but it is only rated up to 30HP.

    You mentioned that you were looking for torque options. The PF755 does have almost 20 torque parameters, while the PF400 only has one; Parameter 13 "Torque Current", which is a read-only parameter which displays the torque portion of the output current.

    It is important to note that with any AC motor there is an inverse relationship between torque and speed. Whether or not your system is set up as a torque (rather than speed) follower, it makes sense that you'd see amp fluctuations with changes in speed or load demand. This might be worse in the 400, which was designed to run best on a modified V/Hz curve for pumps and fans. 

  13. Posted

    Not sure what drive you have but in the PF750 manual, 315 means "The absolute maximum Position Error value has been exceeded".

    This is a configurable alarm, which means the programmer gets to choose what happens when the condition occurs. The programmer felt that "fault" was the best option for your process.

    This is configured in the motion instructions in Logix, so it can't be addressed in the drive, itself. You'll have to look at controller's logic to determine what the max position is programmed to be, and why the drive is exceeding it.

  14. Posted

    @Joe E. I'll have to ask my friend what version of Studio he was using and what controller.

    The e's may or may not be just an annoyance but the real question is, why the invalid expression error? My guess has always been that the AOI was modified off-line and then downloaded. If the problem is with the AOIs. it's almost certainly related to AOI tags or parameters because code errors are not allowed to be downloaded and as you said, AOIs can't be modified online.

  16. Posted

    @VFD Guy has asked a pretty valid question, which @BobLfoot eluded to; different drives treat accel ramp rate differently. If accel is set to ten seconds, some drives will take ten seconds for all speed changes, from current speed to new setpoint, while others assume a zero to setpoint, and scale the difference if the drive is already running. 

    Let us know how the RMP instruction works out for you.

  17. Posted

    @Joe E. The first article you posted is dated Feb 2020 and is for RSLogix5000 (pre-V21). The OP's project is clearly written in Studio5000 V28 or earlier, so the article may be a valid resource for this. However, the E, e, I, i, R,r, and D designations have gone through many changes over the various Studio iterations, and as Rockwell instructor I know firsthand how challenging keeping at all straight can be. In my personal experience, on pre-V21 versions of Studio (and as I recall), as soon as you enter the online editing mode, the top line (the one that's being edited) automatically gets an "e' regardless of whether there are errors. The lower, duplicated line gets an "r". They change to upper case once the edits are accepted but not yet compiled/assembled. They changed the e and E to i and I in later versions. Pain in the butt. Regardless, I've always been trained by Rockwell that "e" means editing, which flies in the face of the article you posted. Go figure, lol. 

    For the OP's problem we're really down to two questions: Why are the "e"s there when he's clearly not in the online editing mode, and why has he got the invalid expression errors.

    I've bounced the first question off a couple of colleagues who both offered the same explanation; someone began an online edit to the controller and then logged off mid-edit without exiting the edit mode. The e's are now permanently in the code. My super-nerd friend who has a demo at home tested this replicated it exactly. The e's were ever-present after the mid-edit disconnect, and showed up on all subsequent re-connects and uploads. The only way he could get rid of them was to download the original project, overwriting the e's. To sum it up, the OP's code will likely have to be uploaded, corrected offline, saved, and downloaded to get rid of those non-online editing mode e's.

    Based on the above responses, I thing we're all on the same page about the expression errors. Something is wrong with his AOIs. I'm thinking it's tag related and he's just going to have to pour over it until he finds the issue. I hate how much of a non-answer that is but I/we don't have the code in front of us. 

    @Dimitry Stepanoffare you able/allowed to post the .acd here? 

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  20. Posted

    The lowercase “e”s mean that that line of code is being edited. Lower case “i”s mean the edits have been accepted (no errors) and are ready to be inserted. A bright green power rail does mean the controller is in the run mode. However, it does not mean that particular routine is being scanned, because it would have to be called by a JSR. 

    All that to say, yes, seeing the e’s next to a green power rail is definitely not the norm. I really wish I could be there in person to drive around in this one myself. 

  21. Posted

    Just to review: An invalid expression error means there's an error in the syntax of the written expression. For example, if I were attempting get the mean average of three tag values using the CPT instruction I would write the following expression: "(Tag1 + Tag2 + Tag3) / 3".

    But what if I screwed it up and added an extra operand, like a multiply right next to an add: "(Tag1 +* Tag2 + Tag3) / 3". This expression now has an error, and the error description will be "invalid expression or tag".

    The same error would occur if I entered a tag that didn't exist, whether it's a tag that hasn't been created or one that has been deleted.

    As you know, errors can not be downloaded to the controller so this will have to be remedied. To try to begin to answer your questions:

    1. You uploaded the project from the controller, and are now finding these errors in the uploaded project? Or did the errors show up after modifications were made to the code? Seems to me like it would have to be the latter because offline errors don't download and online edited errors will not be allowed to be tested or replace existing code in the run mode. 
    2. If any instruction is missing its tag the error will be "Instruction has no arguments specified". If an instruction is missing other vital info (ie, no value written in the "Preset" field of a TON) the error will be "Missing operand or argument". My experience is this rule applies to AOIs, as well, but if anyone has more or different information on this I'd love to hear it. In the screenshot showing the AOI with zeros in the "External_Req", that line of code appears to be in the edit mode (lower case "e"s on the rung numbers) and I believe the 0s and ?s are the controllers way of telling you there's an error here. Any time you see a "?" in Rockwell code there's a problem. Due to the multiple decimal points, I'm wondering if that field is expecting to see data from a multi-dimension array. Or it could just be that's the default filler for missing tags/values in an AOI. I'd like to see the code for the AOI and play with before I said anything more specific.
    3. Since the AOIs seem to be the source of your issues, I would open their profiles to examine their tags, parameters, and logic. Chances are that tags not created in the AOI(s) profile were added to the code as part of the edit, or tags the AOI(s) depend upon were deleted during editing. Hopefully the original programmer left some descriptions in there for you to help understand how and why the AOIs are used, which will help a lot in rebuilding what's missing or corrupted.

    Hope this helps.

  24. Posted

    First off, get rid of that antiquated Drive Explorer tool and install Rockwell's free Connected Components Workbench (CCW). It's a far better and more user friendly drives tool, with many more features. And did I mention it's FREE?

    It sounds like you're using a hard-wired 0-10VDC analog signal in for speed reference, and that you've at least put meter leads on the terminal blocks to verify it's not the wires. I will further assume that you've checked the for the obvious things like loose connections at the terminal blocks, particularly with any feedback devices, such as an encoder (if used). @alan_505 has set you down the right path to start with and the results you get from that check will determine what to do next.

    • If parameter 2 shows an incoming speed reference at or very close to 0 regardless of the voltage on the terminal block, check parameter 545 (Speed Ref A Sel) to make sure the drive is looking at the correct analog input. If it's not, fix it. If it is correct, remember that voltage on the terminal block doesn't automatically mean the drive can see that signal. Go to the analog input parameter (255 for the main control board, 54 & 64 for the 24v extended I/O card analog inputs) to view the raw data coming into the drive. If that's not changing to match what the multimeter says, your analog input channel is likely bad.
    • If parameter 2 shows an incoming speed reference that closely matches the actual input at the terminal blocks, check parameters 935 and 936, Drive Status 1 & 2. These are bit parameters that tell you at a glance what the drive thinks it's doing. All of the bits in these parameters are important but when I'm having symptoms you've described, I always look at P935 bits 4 (Accelerating), 5 (Decelerating), and 8 (At Speed), 26 (At Limit), and 27 (Cur Limit) first. For instance, assuming a correct and good input speed signal, if bit 8 is set and the motor is not moving, you'll want to check your motor's encoder (other feedback device) if you're using one. If it's damaged or has loose wires, the drive isn't getting the feedback it needs to let the motor draw more current. I once found bits 4 and 27 were simultaneously set because someone accidentally changed the current limit parameter to the minimum of 1. The drive was trying to run but no significant current was leaving the drive because the limit had been hit. No faults, no alarms, and no motion. 

    I know you said you believe no parameters have been changed from their known good values, but these are all things that should be checked and positively eliminated as possible reasons for the failure. 

    Keep us posted on your progress and I hope this helps. 

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