valve cluster jitter on device net

[RaphRA]

I am using the NI PCI device net card to read IO's and write to a Festo valve cluster.
Readig the Input is no problem but set outputs flicker every approx. 8 sec for some hundred ms. The Problem continues until I unplug the card connector, stopping the driver or program changes nothing. No matter what bitrate or how many devices I have on the Bus I cannot get rid of the Problem. I also updated to the latest driver version (2.2.1.12291).

I am using a PC-deviceNet Card from Allen-Bradley to setup and debug the Bus and with this device the flicker does not occur. Also the devices on the bus don't set any error bits or go to idle state, also bus communication seems to be fine at all time.

Can anybody help me with this problem?
Thanks in advance!

Raphael

[dhuff]

did you check with the manufacturer to see if you are sending the correct messages? Many hydraulics controllers require a constant stream of messages, to ensure the CAN bus hasn't been disconnected. If you send a command to run the valve, it usually needs to see the same command repeated until you are ready to turn it off.

[RaphRA]

Hi Dhuff

I usually repeat the same message every 100ms, but I tried everything between 1ms, 1s and 10s.
No matter how frequent I repeat the same message the valve falls off after 7.5s.

I used an AllenBradley master to further nail down the problem and could set the outputs without the described jitter. I called our local NI office and returned the card as I suspect a broken controller.

Has anyone another idea why this only happens with these Festo pneumatic valves and this NI master? Everything else works fine (DI/DO)!

thanks a lot

Raphael

Message Edited by RaphRA on 05-09-2005 05:14 AM

[frankwu]

Hi Raphael,

The problem is very strange. Maybe you can try the following ways:
(1) Set PollMode to Scanned. The default mode is Automatic.
(2) Install the new NI-DNET driver 1.4.1 from ni.com

Frank

[RaphRA]

Hi Frank

what you suggest is near to where the problem lies, I now use scanned mode for the "normal" devices and have written my own explicit messaging VI for the Festo valves. Since the Festo valve expects the data to be repeated forever even if unchanged and the NI master knows about the current states and only transmits the changed ones theyr communication is troubled. This leads to the Festo valve resetting every 7secs because its communication times out.

Thank you all for your help!

Raphael

[alessiodamiani]

I have the same problem with FESTO CPV valve terminal.

Can you post the VI you used to solve the problem?

Thank you.

[RaphRA]

certainly, will take some time though as I'm not currently working on this project location..

the solution is explicit messaging, don't remember exactly how I programmed this at that time..

[alessiodamiani]

I solved the communication time out problem using explicit messages, but I get error 10hex on the DeviceError output of "Set DeviceNet Attribute".