CTC PAL "head communication error"

[Jake]

We're having an intermitent error, where after completing all the syringe wash cycles, the syringe/arm just critically stalls over the waste. The message on the PAL display is "head communication error." The log in OpenLab EzChrom under PAL control just says "error." This used to happen rarely, but the error is happening more frequently. This is on an Agilent 7890A with an Agilent-branded PAL. We have a service contract with Agilent, but they're really dragging their feet on this and we need it fixed. The instrument handles nearly 200 samples per day, so we're falling hopelessly behind. One engineer was on-site, checked everything and didn't find anything wrong. Problem persists. An Agilent PAL expert later spent the afternoon here and basically all he did was update the firmware from 4.1.4 to 4.3.0. After spending a few hours re-building all our custom objects and re-training (thanks Agilent!), the same error occurred a few hours into that night's run.

Has anyone had and solved this error? Any suggestions? We need to get this fixed, and the next engineer isn't scheduled to be here for another two weeks. The instrument has 108,000 injections on it. It's configured with the larger wash and waste containers. The stall almost always happens after completing all the syringe wash cycles, although it did stall once in the middle of a wash cycle. But the error always occurs during syringe washing. We have another Agilent, a Agilent 7890B configured similarly, with about 51,000 injections on it, and it just generated this error for the first time few nights ago.

Thanks for any help.

[dlbenach]

I can't be much help except to say we have the same problem exactly as you described. We are running an Agilent 7890A with the Agilent Sampler 80 (ctcPAL) and Empower2 software. I thought it was a software conflict between Empower and Agilent. Agilent service reflashed the firmware but we still get that problem. We also get a lot of other error messages which seem to do with communication failures. We have discussed using the Sampler 80 hand controller to control the injections instead of Empower. Empower would only collect the data. I am not familiar with EZChrome so I'm not sure if that's an option for you.

Please keep the forum updated. I would love to hear if you get any resolution.

Dave

[labstephan]

Hi all,

we had this error message approx. two years ago. A standard suggestion is to reload the firmware. Hope you have a backup of your config. This will save definitely a lot of time with the lovely re-teaching.
In our case this wasn`t so simple. There was one of the flat cables broken and needed to be exchanged. After the service tech did this we had no error message up to know.

On monday I can look what cable was change and post the p/n.

Best regards

Stephan

[Peter Apps]

Any intermittent problem makes me think immediately of loose connections or dodgy cables as Stephan reports. It's a poor show that this has not been fixed by the suppliers - at the worse it would involve troubleshooting by replacing components.

Peter

[tecdd]

We had this message a couple of times now on different machines,and in all cases it appeared to be the x-axis ribbon cable.
Cable shouldn't cost more than 100 Euro. Replacement is a bit tricky but not too difficult

[Jake]

Thanks all for the responses. It really sounds like a ribbon cable, and not that uncommon. Will keep you posted.

[labstephan]

Hi Jake,

Ribbon cable kit for X-axis 80cm (P/N PALCBL80) was the part changed in our Combipal.

You should get this part in US through LEAP or Autosamplerguys. Agilent also sells this but in Germany is 5 fold price than CTC.

Best regards
Stephan

[aldehyde]

There is a ribbon cable that connects to the injection head, if the ribbon cable gets pulled forward it is possible that it can be cut or damaged when the head moves forward and backward. This usually happens during maintenance, the cable tends to fall back into the hole and whoever is doing maintenance pulls it forward too far while attempting to connect it to the head after changing the bungie cords. Sounds to me like someone damaged the cable or it is loose and requires replacement. If flashing the firmware doesn't fix it replace that cable and then check all taught positions before attempting to run.

Regards

[Jake]

We'll folks, finally resolved. This was getting ugly, and getting progressively worse on two of our five middle-aged Agilent 7890//PALs (110,000+ injections on one; only 54,000 on the other). I won't go through the details of what Agilent did that didn't work (seemed like a waste of time to me), but just the solutions. On one, the issue was that the gas flush tube was obstructing the free movement of the cable. A small portion of the tubing was cut off, and we haven't had the problem since. Agilent tried the same tactic on the other problematic GC, but it didn't help in that case. Since we don't do head-space, the entire gas flush tube was removed and the x-ribbon cable was replaced. This solved the problem on that GC. Agilent did the right thing by providing a new gas flush tubing kit and agreed to re-install in case we ever want to do head space on that GC . A nice jesture.

Thanks all for the helpful feedback.

[Peter Apps]

Result ! - thanks for posting the solution.

Peter

[Jake]

I guess I spoke too soon. The PAL on the instrument in which only the gas flush tube was cut is back to throwing the error after a few thousand more injections. The plan now is to replace the ribbon cable and remove the gas flush tubing on that one too. The other instrument where this was done is still working fine.