Shimadzu / Dionex RF10AXl / RF2000 strange behaviour

[Alex Buske]

Good morning,

We have recently bought two RF10AXl (newer grey series) and converted them with Dionex EPROMS to RF2000 (V9.80). They are connected with serial cables to Chromeleon IPCs (6.80, SR6).
Sometimes they show strange behaviour: they start at 999.9 mV (display: OVER) drop to 0 rise again to 999.9 mV. They can be manually autozeroed, but suddenly rise again. Programmed autozero doesn't seem to work everytime.
This behaviour occurs when the lamp is switched off and later switched on again by the software. Switching the detector off and switching it on again doesn't result in that behaviour.
We have also observed that effect in a sequence with wavelength/sensitivity switching.
I have tried different COM-ports at the IPC and the Shimadzu service has already exchanged the HV-board with no success.

Any ideas, comments...?

Cheers,

Alex

[Hfranz]

Alex, I would like to encourage you to order these things directly from Dionex. As you can see, it can put you in a difficult position if such a mixed approach fails. Anyway, I want to help. It is possible to install the firmware incorrectly. The notch of the EPROM must be directed away from the rear. Might be that the strange effects you abserve are a result of incorrect insertion.

[Alex Buske]

Thanks for offering help.
I know that mixed approaches are not always easy. These EPROMs were bought to convert existing RFs as part of a larger deal that was cetainly more expensive than just two instruments.
Things are getting complicated:
The method is running well on older RF-10 with V9.8 firmware.
The service engineer has replaced the HV-board with no change.
He has exchanged the main board with the board from a retired RF-10/V9.80 - again no change, problem consists.
Then he checked performance with V3.33 firmware and optical connction to the SCL - everthing was working o.k.
The intrument was also working correctly with V9.80 firmware when controlled via optical connection from the SCL.
Our problems came up again as soon as the RF-10 was connected via RS2323 to the Chromeleon IPC.
Also, the signal jumps occur only with one of the settings (292/356 nm, low sensitivity), never in the second setting (280/310 nm , med sensitivity).
I am getting confused.

Alex

[ivanvins]

Based on the description I will suspect a bug in the Chromeleon software driver - try to contact Dionex on this. Especially if it is related to low sensitivity settings (I guess other wavelenghts will behave the same way)

Other thought - in case it is observed only on one from two or more identical setups, I will suspect the lamp or its source - it may start slower than the program expects.

Puttng the chips opposite way will result in no function, I doubt it could result in the encountered behaviour.

[Alex Buske]

Based on the description I will suspect a bug in the Chromeleon software driver - try to contact Dionex on this. Especially if it is related to low sensitivity settings (I guess other wavelenghts will behave the same way)

The driver worked on older detectors of the same type (same IPC same COM port). If it was the driver, I would have been surprised to see the 'signal: OVER' on the detectors display. Sure I have contacted Dionex and Shimadzu.

Other thought - in case it is observed only on one from two or more identical setups, I will suspect the lamp or its source - it may start slower than the program expects.

The whole thing works when the detector is controlled via optical link from the SCL - so I would exclude the lamp.

Thanks for the input.

Alex

[MeTooOne]

Hello Alex,

first of all - im not a native english speaker.

We have had exactly the same problem 2 years ago. Its tricky. Let me explain...
Your detector signal only allows some digits below zero. If more - he signal will end in error (or something else).
Your detector zero signal is adjusted near the lowest signal that can be shown by the detector without error. So if your signal will go only some digits into the negative range an error (let me call it <under> instead of <over>) will occur.
Now to the tricky part: Your CM software can not differ between <under> and <over> signal error. So it sends an over error to the software and will cause in a signal 999.9 mV <over>. The guys at Dionex should know this since two years!
Last but not least: You can adjust your zero signal. Press zero at the detector an shift your zero point up. So the electronical value of zero will internaly adjustet to a higher voltage signal (its been described in the manual). After that, a slightly negative signal will not end in error.

Hope this can solve your problem.

[Alex Buske]

Hi,

Thanks for the input. I am also not native speaker. Your description was easy to understand.

I cannot enter the Baseline_Shift into the RF, because the value is overridden by Chromeleon. However, I entered Baseline_Shift Values in CM programs (0 and 50mV, out of 250 max value). At our second detector there was no effect of the differtent Baseline_Shifts, the chromatograms look like a fence (not in each sequence, only sometimes when the detectors was used (without problem), lamp switched off and lamp switched on (by CM) a few hours later.
On our first detector (HV board exchanged, lamp replaced by an old one) there is just a 999.9 mV spike after switching wavelength & sensitivity - no matter what I enter for Baseline_Shift.
I have just installed the "new" lamp and switched it off. In a few hours I will switch it on and measure again.

Alex

[fcozzi]

Dear Alex,

I have a question for you: I would like to do the opposite i.e. we have a RF2000 and we would like to convert it to a RF10AXl...

Do you by any chance any idea how to replace the EPROMs? Do you have still the RF10AXl EPROM?

Thank you

[fcozzi]

Just a quick update: if you own a Dionex RF-2000 is possible to connect it to a Shimadzu CBM-20A without exchanging the EPROM with a Shimadzu one - the one inside the instrument is already a Shimadzu one...

[eg@aaclab]

Does anyone know if a Dionex RF-2000 will work with a 10 series Shimadzu HPLC system (SCL-10A or SCL-10AVP controllers? We found a used one for a good price but not sure if it will work with either 10 series controller. Thanks Eric