automation direct 05

I HAVE 900 MHZ RADIOS HOOKED DIRECTLY TO AUTOMATION DIRECT 05.THEY
WORK FINE BUT OCCASIONALLY WILL QUIT COMMUNICATING.THIS IS A SCADA
NETWORK.WHEN THEY QUIT COMMUNICATING I HAVE TO DRIVE OUT TO THESE REMOTE SITES AND POWER DOWN THE PLC'S AND POWER THEM BACK UP AND
THEY WILL COMMUNICATE AGAIN.


WHY DOES THIS HAPPEN !!!

Well....it's hard to say. I think more info. would be helpful.

1. is the PLC stopped?
2. if has the cpu reported errors?
3. do you have any that work all the time....not problems?
4. do the radios use hardware handshake? (may be hard to tell)

Ok...suppose that the PLC is not stopped. That means we need not worry about question 2 and can go on.

If you have some sites that work and some that don't but are the same configuration we really need much more info.

However, if all the sites do the same thing, you may want to put a breakout box on the data line to the radio. You see, if the radio needs hardware handshake and your plc doesn't really provide it by checking each frame for completeness (is that a word??) then the PLC may not cycle RTS or CTS correctly and confuse the radio. This is a real problem on SIMPLEX radio channels because all radios transmit and recieve on the same frequency so all the slaves hear most of the other slaves and the master and the master hears everyone. All one needs is a timming glitch and then one PLC or another sets CTS before the radio sets RTS or both are set at the same time so the radio is waiting for the PLC and the PLC is waiting for the radio so everyone is waiting and no one is talking. Now you turndle up and cycle the power thus clearing the fault and bingo away she goes.

So in short, if there is not obvious PLC fault, look for confusion on the hand shake. Without more info. on the radio and such that's the best I can do.

Anyone else??

Note on question 4. Some radio spec.'s will say that they use DX keying or hardware handshake. What they are trying to say is that if a complete hardware handshake is not there the radio will infer the handshake by looking at the CD or TX data line and timming out. This is a headache for sure.

Good luck
Lenny

Hammer, do a search on the AutomationDirect.com web sites technical discussion forum or else contact the tech support staff. There are/were some issues with the response of the DL-05 to power dips. I believe these have been addressed with a firmware update.

Hammer, are these units running right off the utility, or on a UPS ?
I did have a problem where the utility had put in the bare ( in more ways than one) minimum line , and every once in a while, when two or so loads came on at the same time, the voltage drop was enough to recycle the PLC. First fix was a UPS, then a meeting with the power co... got my new line !!!!
David
beerchug

The latest version of 05 firmware on AD's website fixes the power flicker problem.
http://ftp.automationdirect.com/firmware/FirmwareOnly/d05v424.zip

That's the link for the firmware.

If you don't have the firmware tool, here is the link for it:
http://ftp.automationdirect.com/firmware/updatetool2_0_4.zip