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Post by Lake Shore Jeff M on Feb 8, 2019 8:42:58 GMT -5
If your system has a large thermal mass, you may never be able to get it to oscillate. P is a multiplier of the error in temperature. You can figure its scaling out by setting P to say 100, I and D to 0, and then put in a fixed error. So if the reading is 20 K and you put in a setpoint of 21 K, the heater will turn on to a certain percentage. The P scaling is just the amount of heater percentage per K.
In regards to updating the firmware. Version 1.5 is about 9 releases behind so I would highly recommend doing the update, although, there are no defined changes for the regulation or Autotuning functions.
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Post by Lake Shore Jeff M on Feb 8, 2019 8:17:28 GMT -5
Hello snehal,
Since the meter is unable to determine the frequency, we may need to have the Model 455 and probe returned to the factory for analysis. Before we do that, please let me know the model number of the probe you are using.
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Post by Lake Shore Jeff M on Jan 28, 2019 12:52:35 GMT -5
Hello Fred,
The two power supplies you have were manufacture discontinued more than 15 years ago so we can only provide limited support as we have no one at Lake Shore that has ever used these supplies. Are you using the 601 control unit or just the two supplies? With the 601 control unit installed we believe the current should be shared, however, we are not sure how it operates without that unit.
Looking at the User Manual it looks like you have everything configured correctly so I would recommend increasing the current by 15 to 20 Amps and seeing if the supplies start sharing the load. If they do not share the load, you could try going to 130A and seeing if the second supply comes on once the 622 reaches its 125A maximum output.
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Post by Lake Shore Jeff M on Jan 8, 2019 8:48:28 GMT -5
Hello Srinivas,
The MeasureLINK software that you will use to configure the Model 240 actually has two different PT-100 standard calibration curves that you can select. As you indicated, the IEC PT-100 curve cannot measure temperatures below 73.15K (-200C) where the LSC PT-100 curve will read down to 28K.
Using the IEC curve, any temperature below 73.15K will produce a T. Under error and the LSC curve will produce the same error at temperatures below 28K (-245.15C).
However, since you do have the calibration files for your sensor, I recommend that you load that file into the Model 240 for best accuracy.
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Post by Lake Shore Jeff M on Jan 3, 2019 7:58:34 GMT -5
You can find a detailed explanation on the calibration method and polynomial fits we use in Appendix D of our Temperature Catalog. Here is the link:
www.lakeshore.com/Documents/LSTC_appendixD_l.pdf
The information you want to read starts on page 100,
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Post by Lake Shore Jeff M on Nov 30, 2018 8:12:57 GMT -5
In order to assist in the troubleshooting, I will need additional information. Please let me know the following: Model and/or serial number of the sensor How you are making the leakage current measurements What is the resistance between leads I+ & V+, I- & V-, V+ to V- Also, measure between each lead and the sensor package or the chassis if the sensor is mounted.
With this information, I can determine what may be causing the leakage.
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Post by Lake Shore Jeff M on Nov 29, 2018 12:01:47 GMT -5
Thanks For the post Francois.
So that everyone knows the full story, we also provided an updated initialize.vi for your 2016 Labview application which resolved what we saw happening in the initial issue you reported. We will provide the new .vi to National Instruments and they will post an updated version of the Model 372 Driver within the next two weeks
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Post by Lake Shore Jeff M on Nov 26, 2018 15:29:57 GMT -5
Hello francoisp,
It seems that we may have a bug in our model 372 driver. Your trace capture shows no response to *IDN?
If you look at the ‘initialize.vi’ in the 372 driver, it appears it’s sending *RST before it updates the COM port settings (parity, baud, stop/start bits). This causes an error state and the COM port to be messed up. We were able to see a similar problem when I ran the driver at my desk.
We have an updated VI that I would like to send you so please send me an email at service@lakeshore.com so I can forward the updated VI to you for verification that it resolves the issue.
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Post by Lake Shore Jeff M on Nov 15, 2018 14:21:41 GMT -5
Thank you for letting me know the issue was resolved
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Post by Lake Shore Jeff M on Nov 14, 2018 15:53:40 GMT -5
As a starting point, please verify that the setpoint limit value in the sensor curve file you have assigned to input B is not zero. To do this, verify what curve you have assigned to Input B and then use the curve entry button to edit the information. Press Curve Entry then select Edit and press enter. Next select the curve you are using and press enter. Press enter until you see the Setpoint Limit Entry and verify the value is equal to or greater than the setpoint you want to enter. Press enter again and then press the escape key to return to the normal display. If this does not resolve your issue, please contact us at service@lakeshore.com or call 614-891-2243 and select option 2 for service between the hours of 8:00 AM to 5:00 PM Eastern time.
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Post by Lake Shore Jeff M on Nov 13, 2018 15:06:20 GMT -5
You are correct that the signal (Center pin of the BNC) needs to be connected to Pin 1 of the D-sub connector. The shell of the BNC connector can be connected to any one of the three ground connections.
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Post by Lake Shore Jeff M on Nov 1, 2018 10:23:33 GMT -5
Yes, it is possible to switch from LN to LHE during a cool down with the understanding that the cool down time will be longer and that the process creates potential for blockages to form in the transfer line or refrigerator.
If you send me an email to service@lakeshore.com and provide your contact information so I can send you a link to download one of our newer manuals which has the procedure you would use.
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Post by Lake Shore Jeff M on Oct 24, 2018 11:20:19 GMT -5
The SD package is completely isolated from the sensor material by use of a sapphire plate placed between the sensor and the package. This allows for the temperature of the measuring area to be transmitted to the sensor and provides the electrical isolation to the package.
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Post by Lake Shore Jeff M on Oct 18, 2018 7:15:00 GMT -5
I have discussed your question with my applications engineer and due to the complexity of your question, answering it in the forum will be very difficult, therefore, they have asked me to obtain your email address so please send this request to service@lakeshore.com and I will have our applications engineer contact you directly. Please be sure to include your contact information including your full name, company, address and contact telephone number.
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Post by Lake Shore Jeff M on Oct 11, 2018 12:24:34 GMT -5
I checked with our design engineer and he informed me that when you power on the Model 475 with the hall sensor connected directly it will display an Invalid Probe error. If you press enter, it will bring you to a screen to enter the nominal sensitivity and the Gaussmeter will then display a field and not resistance. You will need to enter the sensitivity every time you power cycle the Gaussmeter. If you press enter without entering the sensitivity, it will display in resistance.
He also confirmed that this does work in all measurement modes, DC, AC and RMS
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