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
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Received on Fri Apr 03 2026 - 07:36:54 MST