VFD speed control via Panelview HMI (FactoryTalk ME Studio)

[Dan Col 0]

Hi all, I have one of my first jobs using an AB Panelview Plus 1500 screen. The job is to connect a CompactLogix (L36) Panelview Plus 1500 and 34x Powerflex 525 VFD's all over ethernet switchs (AB Managed switches) I have had the system working but now my client wants to add some HMI screens which would allow a manual start/ stop function for each drive and a display to show what speed each VFD is running at and a Numeric input button, of some sort, to allow the operator to add a new frequency and change the speed of that VFD on the screen rather than having to open the control panel and change the VFD parameters. I am very new to Allen Bradley and have sorted out the basics of the PLC programme and the HMI but now need to know what i need to add to the screen to allow me to change the speed and view the speed the drive is running at and how i programme the PLC to do this? If anyone can help that would be great, thank you. Regards Dan

[b_carlton 61]

Before you worry about using the display you need to work out the PLC control of the drives. After that the display will just show the numbers, send requested numbers, show and request the functions. Is the PLC in communication with the drives right now? If so, how? If not, that will be the first (and frankly the more complex of the jobs) Edit - I see from the specs (I haven't used these) they have embedded Ethernet I/P. That should make integration with the CompactLogix a little easier. Edited 1 Jun 2013 by b_carlton

[Dan Col 0]

Yes the PLC is in communication with the drives right now, all via the embedded ethernet and all through ethernet switches. Once in RSLogix5000 i was able to add the new moduels to the Ethernet tree, assign the IP addresses and then use the embedded I/O to send a run and stop command to the drives, i believe there is a bit that i have recently discovered that is a frequency display (will give the frequency that the drive is running at) so i could use this for the display however it is the PLC programme that is holding me back in terms of what function blocks would i be looking at to display this information on the screen, i assumed a register or move command that i would give a tag name to, but this is what i am not sure of. Its the issues with the PLC programme to show the current speed and input a new speed, tying them together through the PLC programme is the issue. Thank you Dan

[dmargineau 6]

There isn't really a dedicated RSL5K instruction for retrieving data from an integrated system component. As a general rule, for any system "embedded" device (conected as a system module) there is a default read/write data packet which is automatically created (and transfered) at the moment of the module's addition to the controller's project. For a VFD, there are two Read Words and two Write words; the first Read word is generically called Status and it is to be examined by the application at bit level ( At Speed, Stopped, Faulted, etc.); each Read word #1 bit's state informs the application about the status any of the drive's functional parameters; the second Read word is to be examined as a whole (word level) and it constitutes the Feedback of the drive's output, in your case the Frequency of the load side of the inverter. Correspondingly, the first Write word represents the Command and it is examined by the application at bit level; the state of each bit represents the controller's application resulting logic commands to the VFD's processor ( Run, Stop, etc.); the second Write word is the Reference, it is examined at word level and represents the Speed (Torque) reference the user application is commanding the drive to output. In your case, the HMI application will need to "connect" to the corresponding RSL5K tags automatically created for the respective device at the moment of the module's addition. If additional information needs to be Read From/Written To the drive, you could expand the size of the default data packet exchanged between the CPU and the drive by the use of the Datalinks; at any time, you could also use Explicit Messaging (MSG) in order to access the drive's CIP Objects and retrieve/write between the the controller and the VFD's processor. The User Manuals for the VFD and the drive's communication adapter have the answers for all your questions and also provide you with functional examples. http://literature.rockwellautomation.com/idc/groups/literature/documents/um/520-um001_-en-e.pdf http://literature.rockwellautomation.com/idc/groups/literature/documents/um/520com-um001_-en-e.pdf Edited 3 Jun 2013 by dmargineau

[HKU_MS 0]

You might want to look into DMAT drives and motion accelerator toolkit. I havn't used it on a project yet as I don't do much with drives but seemed fairly strait forward in an online demo.

[HKU_MS 0]

You might want to look into DMAT drives and motion accelerator toolkit. I havn't used it on a project yet as I don't do much with drives but seemed fairly strait forward in an online demo.