Speed reference on Dnet with a PF 753

[Automatoes 0]

Houston, we have a problem!! I have here four PFlex 753 on Dnet, I just cant send to them the speed reference throw the Dnet connection, I can turn them on and off and get some status from them, but I cant send the reference speed, I believe I'm missing some config on the drives, I already try to make some changes on parameter 545 (Speed Ref A), but it doesnt works. Best regards and sry about poor english.

[Steve G 1]

What PLC are you using and what comm card are you using

[Automatoes 0]

Controllogix 1756-L61 with a 1756-DNB

[dmargineau 6]

When the drive is first connected to an operational communications network the on-board processor will self configure and "relate" itself to one of the seven (eight for PF 755) "Reference Ports". The current Speed Reference Source could be also retrieved via P930. It will point to the parameter number which contains the value of the current Speed Reference. Send a 32 bit (REAL) value from your PAC (intended speed reference)and monitor P871 through P878 within the drive's interface (HIM or Drive Executive). One of the seven parameters should be receiving it. The number of the parameter receiving the speed reference (871, 872,...878) should be entered as the value for P545 (Spd Ref A Sel) which is usually "defaulted" to 871 (Port 1). The drive should be operating in "Auto" mode in order for the on-board processor to use the network delivered Speed Reference. Edited 2 Jun 2011 by dmargineau

[Automatoes 0]

Sure, I was already sending the 32 bits (DINT) reference from my PLC, but I think the reference parameter are wrong on the drive, I'm using the "Port 4" reference speed, Ill follow these steps and post here in a few moments...

[Automatoes 0]

Hummm.. Doesn't works, I throw a speed reference on logic and couldn't find it on Powerflex, I think its some drive network config, but I cant find it...

[dmargineau 6]

On page 138 of Rockwell Automation Publication 750-PM001A-EN-P, P871...P878 (Port Devices Generated Reference Value) Data Type has to be REAL. You have stated that the Reference Value you are sending on DNet is a DINT Data Type one. Since P2 (Comanded SpdRef-Read Only) is also a REAL Data Type, maybe you should try sending a 32 bit REAL value as the Reference. Since it is a fairly new product, I am not very familiar with this kind of application. We have had a few PF750 generation AC drives installed without any major comissioning issues.