Hi AMMRL group,
I have a follow up question concerning our VTU probe heater on our EPR that
I hope someone can help me with.
After some more trouble shooting I am more convinced that it is a
PID/Calibration file issue rather than a hardware issue.
In the web access page under the VTU controller parameter page there is a
PID controller table. If I put in PID parameter values the heater turns on
and stays on. In this way I can run VT experiments.
My question is where are the PID calibration files supposed to be located
in Xenon and what is the format?
I know other calibration files are located in the FUSTUP folder. Within
that folder there is a FUVtuCtrl folder. There was nothing in that folder,
consequently I tried adding PID tables in various text formats. That has
failed to change the behavior.
In the VTU application in the software there is a VTU Calibration tab with
an option for PID parameter. There is an option to load files but in the
drop down menu it just has none listed. The table itself is grayed out with
no option to enter values manually.
My thought is I am not adding the PID tables in the right place/places to
make it readable for the software.
thanks
On Fri, Apr 3, 2026 at 7:36 AM Jaya Nolt via groups.io wrote:
> Thanks Chuck.
> We did take resistance measurements for the heater. For the safety sensor
> 1.8, and other pin measurements of 0.2 and 6.
> I don't have a manual for the unit. I am hoping to get some more info from
> Bruker soon on what the numbers should be.
>
> best,
> jaya
>
> On Thu, Apr 2, 2026 at 11:23 AM Charles Hanson via groups.io wrote:
>
>> Hi Jaya,
>> I think the problem is either the heater is shorted and the VTU is
>> drawing too much current or the VTU for some reason isn't able to provide
>> current to the heater. So the unit applies a voltage and the current
>> limiter kicks in because it is measuring too high a current and cuts the
>> voltage back down to zero. In the manual it may specify what the heater
>> resistance should be. Anyway I would measure this first.
>>
>> Cheers,
>> Chuck
>>
>> On Thu, Apr 2, 2026 at 2:06 PM Jaya Nolt via groups.io wrote:
>>
>>> Hi Ammrl group,
>>> I am looking for some troubleshooting help with our probe heater. Our
>>> EPR is running Xenon with the VTU device.
>>> Software says probe heater is OK however no heater power comes on, and
>>> it stays at 0%. In the webpage I can turn on the heater briefly by clicking
>>> on the options for 10%, 30% etc. I can see the heating effect and then the
>>> percent drops back to 0.
>>> One guess is that the heater safety sensor is not working properly.
>>> The other guess is that the PID values have been comprimised.
>>> In the software VTU controls there are no PID values listed in the
>>> table, it is grayed out, and loading PID values is not supported. This
>>> seems odd but I don't have any documentation otherwise. Also I cannot find
>>> anything in the calibration files for VTU values.
>>>
>>> Thanks for any thoughts in advance.
>>>
>>> Jaya
>>>
>>>
>>>
>>>
>>>
>>
>> --
>> Charles Hanson
>> Assistant Director, Magnetic Resonance Center
>> Boston College
>> Merkert 107
>> 2609 Beacon Street
>> Chestnut Hill MA 02467-3860
>> Tel (617) 552-6903 (office)
>>
>>
>> https://www.bc.edu/content/bc-web/research/sites/vice-provost-for-research/about/research-facilities/nmr-center.html
>>
>>
>>
>
> --
> Jaya Nolt
> R & D Engineer
> Spectroscopy Facility
> Materials Research Lab
> Office: (805) 893-4997
> Email: jaya_at_mrl.ucsb.edu
> http://www.mrl.ucsb.edu
>
>
>
--
Jaya Nolt
R & D Engineer
Spectroscopy Facility
Materials Research Lab
Office: (805) 893-4997
Email: jaya_at_mrl.ucsb.edu
http://www.mrl.ucsb.edu
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Received on Mon Apr 13 2026 - 15:27:02 MST