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Post by Lake Shore Ogi on Apr 16, 2018 15:43:43 GMT -5
Dear Kerry,
Your question is somewhat tricky to answer but I will provide you with some hopefully useful information. Considering that our Model 218 monitor only uses a 10 uA constant current source, you should be able to achieve some kind of temperature monitoring using the same method. The instrument, however, has an input impedance limitation of 7.5 kOhm, which limits the ability to read the Cernox 1080's to at minimum of 50K or greater. Anything lower would not work on that monitor.
I would suggest you testing your circuit and keeping excitation current as small as possible. Going lower on the excitation current has also its limitations and challenges but hopefully you will be able to achieve monitoring without causing too much self-heating of the sensor. I regretfully don't have a chart or some kind of reference I can share with you on self-heating with our sensors.
Best Regards, Ogi K.
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Post by Lake Shore Ogi on Apr 11, 2018 7:48:52 GMT -5
You're very welcome. Yes, this will work but please highly consider setting a maximum temperature limit (if you haven't done so already) in order to protect your system. Open loop can be dangerous in certain situations because there's no feedback and the controller will keep outputting power indefinitely (or until something is damaged due to overheating).
Greetings!
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Post by Lake Shore Ogi on Apr 6, 2018 13:09:29 GMT -5
Hi!
Another way to do this is to set the manual output to a low percentage, which will give you a constant power output as you initially asked. The only CAUTION I have with this is that the instrument will be outputting a constant power and won't stop after you reach your setpoint. You would absolutely have to make sure that you enter a maximum temperature limit in your sensor input settings to protect your system in case you or someone leaves the experiment while you're warming up your system. If a set temperature maximum limit is reached, the controller shuts all heaters off to prevent an overheating scenario.
Greetings, Ogi K.
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Post by Lake Shore Ogi on Apr 5, 2018 15:09:36 GMT -5
Hello!
You could use setpoint ramping, which will give you a smooth and continuous control from one temperature to the next - avoiding that maximum output power scenario.
If you have any questions, feel free to give us a call in our service dept.
Best Regards, Ogi K.
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Post by Lake Shore Ogi on Mar 5, 2018 9:31:31 GMT -5
Dear Jack,
Can you first confirm that you're using a pulse-discharge magnetizer for this operation? It should be possible to do what you are asking about and the first thing to do is to make a custom coil such that it is sensitive enough to produce a measurement but at the same time doesn't overload the instrument's input (pulse X # of turns) upon discharge. Are you able to wind your own coil?
The Model 480 has an absolute limit of 100V to the input but we recommend staying at or below 60V. Once you have a coil that works properly to measure the pulse, automation via custom software can be achieved. You would need to write your own software that can communicate over GPIB. Besides using standard and common programming languages, LabVIEW would also be one of your options.
Thanks and Regards, Ogi K.
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Post by Lake Shore Ogi on Feb 19, 2018 10:40:48 GMT -5
Dear Jack,
I'm looking into this with our magnetics applications engineer and will get back to you soon.
Thanks, Ogi K.
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Post by Lake Shore Ogi on Jan 15, 2018 11:31:20 GMT -5
Hello!
Thank you for posting and sending us an email to service. Per my email, it appears that your user curve was not in the right format. Our instruments require NTC type sensor curves to be in log-Ohms/Kelvin. A common mistake that users make is that they keep the curve in Ohms/Kelvin format. For reference, below is the curve header and first three points how they should look:
Sensor Model: CX-1010-AA-0.1L Serial Number: X##### Data Format: 4 (Log Ohms/Kelvin) SetPoint Limit: 325.0 (Kelvin) Temperature coefficient: 1 (Negative) Number of Breakpoints: 192
No. Units Temperature (K)
1 1.47506 325.000 2 1.47957 319.000 3 1.48380 313.500
Greetings, Ogi K.
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Post by Lake Shore Ogi on Dec 15, 2017 13:12:52 GMT -5
Dear John,
This may require a little more troubleshooting than a few messages back and forth over this forum thread. Can you please send me an email to service@lakeshore.com with the following details: 1. Details on how you performed the measurement (was a diode or anything connected to the 335 or did you connect your DMM directly to the input) 2. What pin #s you were probing 3. Details on your input configuration/settings 4. If you try the same test on the other input, do you see the same results?
Thank you, Ogi K.
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Post by Lake Shore Ogi on Nov 20, 2017 14:39:48 GMT -5
Hello Loc, Our applications scientist recommends PELCO® High Performance Silver Paste – available from Ted Pella. It provides good thermal conductivity across the temperature range in question and, so long as you stay below 500 K, should be removable.
-Ogi
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Post by Lake Shore Ogi on Nov 17, 2017 15:18:50 GMT -5
Thank you Loc - I should have an answer for you on Monday! Have a great weekend. -Ogi
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Post by Lake Shore Ogi on Nov 16, 2017 12:23:03 GMT -5
Dear Reza,
Let's keep working through email as we already have instead of through here.
Greetings, Ogi K.
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Post by Lake Shore Ogi on Nov 16, 2017 12:21:51 GMT -5
Dear Loc,
I assume that your annealing temperature is higher than 250K - please clarify. Also, what is the model of your Hall system?
Thanks, Ogi K.
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