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Post by Lake Shore Cosmin on Nov 10, 2023 16:36:26 GMT -5
Hello, unfortunately, programing and scripting is not possible in the older systems architecture. We've encountered over the years customers, like you, who have this need and we've implemented complete and full control scripting for our new 8600 series VSM.
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Post by Lake Shore Cosmin on Feb 9, 2023 14:35:35 GMT -5
Sample Saddling
The sample should be positioned at the geometric center of the pickup coils, a procedure known as "saddling." On a standard electromagnet system, the saddle point is found by finding the local extrema of the moment signal in the x, y, and z directions. Generally, the x (left to right) position should be a local minimum in the moment signal (or its absolute value, to be precise). The y (front to back) position is a local maximum, and the z (up and down) position can be either a maximum or a shallow minimum between two maxima, depending on the separation between the coils. For very weak samples, it is a good idea to saddle using a strong sample (such as a saturated nickel standard), with the same geometry as the weak sample, attached in the same manner as the weak sample to be tested.
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Post by Lake Shore Cosmin on Feb 9, 2023 14:32:24 GMT -5
For more guidance on this, see Section 4.3.3. in the 7400-S Series VSM user manual, which shows moment vs. position on all three (X-Y-Z) axes. It explains how much moment is affected by a sample being off-center.
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Post by Lake Shore Cosmin on Feb 7, 2023 12:59:20 GMT -5
Hello, I guess you are referring to saddling or centering the sample and not actually calibrating the moment gain of the magnetometer. You can saddle the sample using a sample with same dimensions but larger magnetic moment, such as a piece of credit card stripe and then substitute with your low moment sample.
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Post by Lake Shore Cosmin on Nov 23, 2021 14:47:13 GMT -5
Dear Alice, Please contact us via support@lakeshore.com for a faster response. The m vs. time experiment, like all the 7400 VSM experiments, has a few seconds delay before taking first data point. Since you are looking at fast evolving material magnetization you could try to edit the time domains so the points are acquired faster, just like you did for temperature domains in the past OR manually ramp the field while recording m vs. time. The experiment should be configured with minimum time constant and averaging and should be started before ramping down the field. For field ramping, you first need to figure out what current you need for 18kOe and what current will then bring the field down to 0 Oe. Once you know these 2 current settings, you are ready to start recording m vs. time and then you manually ramp the field. The EM Power Supply has to be set for local or internal control in order for you to be able to set a current from front panel. Because it is quite a fast ramp, the VSM may detect the change in field as "fake" moment so I am not sure if it will work for you.
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Post by Lake Shore Cosmin on Sept 23, 2021 10:05:45 GMT -5
Hi Jeff, The software does use Java and indeed this creates problems depending on customers software configuration. Please contact us at support@lakeshore.com and we'll try to help. Thank you,
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Post by Lake Shore Cosmin on Sept 23, 2021 10:02:27 GMT -5
Hi Jeff, Model 218 user manual chapter 6 lists the communication commands and explain the interface setup for both serial and GPIB interfaces. Most likely, LabView can interact with instruments over any available interface. We however don't offer LabView programing support as this is not our product and our LabView technical expertise is limited. To help users using LabView get started, NI offers examples of short programs for most Lake Shore instruments on the LabView support web page. Please contact us for further support of Model 218 via e-mail: support@lakeshore.com Thank you,
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Post by Lake Shore Cosmin on Sept 1, 2021 10:25:38 GMT -5
Dear Alice, In my previous reply I mentioned temperature domains adjustments – settle band and settle time. Did you try that? The VSM oven can ramp as fast as 10 deg/min but depending on the sample size and mounting, its thermal inertia may lead to a lag of the sample temperature behind the indicated temperature.
You can always set the ramp rate in domains to 10 deg/min. The settle band and settle time are the determining factors for oven speed.
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Post by Lake Shore Cosmin on Aug 25, 2021 13:14:46 GMT -5
Dear Ying Zhen,
Because the VSM oven heats the sample mostly by radiation and by conduction (no convection) it is inherently slow, in order to allow sample temperature to follow the sensor temperature. The default parameters will ensure compliance with temperature accuracy specs. If you can accept an increased mismatch between sample temperature and readings, you can edit the temperature domains for your specific measurement. You would want to decrease the "settle time" and increase the "settle band" in addition to increasing the ramp rate you've already tried. For example you can use "settle time = 0.1min" and increase the "settle band = 5C", etc.
The concept of modifying a domain to increase speed is extremely useful also for field when you measuring FORC.
Please address these type of enquiries to service@lakeshore.com for a faster response.
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Post by Lake Shore Cosmin on May 28, 2021 11:47:17 GMT -5
Hello Seungmo,
The sample size should be as close as possible to the calibration sample’s size (3 mm diam sphere). That is why we recommend measuring samples that fit on the sample holder. That means approximately 5x5 mm max for thin films.
You are correct in your assumption that a larger sample's edges will not be detected as well as a “point” sample.
For continuing the discussion, please write us an e-mail at support@lakeshore.com. Please be sure to include your contact info and affiliation. Best regards, Cosmin
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Post by Lake Shore Cosmin on May 11, 2021 12:47:12 GMT -5
Hello Alice,
We understand that the malfunction of your EM power supply affects your research work. We are communicating with Omega's service engineer almost every day about this and we are trying first to find the problem. We hope that is something that can be fixed locally but, unfortunately, the Model 648 may need to be sent to Lake Shore for repairs. Modern electronics are increasingly difficult to repair on-site, despite the service engineers efforts and commitments to help our customers. I think you are right in your assumption that a power transistor have failed, as this is most common failure mode. Because the difficulty of replacing them and because other components may be affected as well, most of these repairs are done at Lake Shore. Together with our rep, Omega, we are very close to provide you a conclusion and recommend the repair. You will hear from us in 1-2 days.
Thank you and best regards, Cosmin
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Post by Lake Shore Cosmin on Apr 15, 2021 22:20:35 GMT -5
Hello, We are aware of the malfunction and we'll work together with your representative to further diagnose. Omega Scientific Taiwan already contacted us and we'll respond as soon as possible.
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Post by Lake Shore Cosmin on Oct 8, 2020 6:12:33 GMT -5
Hello Zhao, Please write service@lakeshore.com from your institution e-mail and please include the address and other contact info. Although the support for Model 7300 VSM for discontinued, we'll do our best to advise and troubleshoot. Thank you,
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Post by Lake Shore Cosmin on Aug 20, 2020 12:16:54 GMT -5
These tests and details are very useful! I will consult with our engineers and then respond to you, most likely by-email.
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Post by Lake Shore Cosmin on Aug 19, 2020 19:52:35 GMT -5
Please contact us at service@lakeshore.com with your name, address, institution/company contact info and the serial number of the misbehaving power supply. We'll open a service case and will forward the symptoms and other relevant information to our engineer in charge with this product line. If a repair is needed, we will inform you of the steps to follow. For testing purpose, we may ask you to run your power supplies on a short instead of the actual magnet. We would also ask you to run the unit under test, alone, on a short instead of the magnet. Generally speaking, the Model 625 is a current source and the current sources should only be connected in parallel. I guess you are not actually connecting them in series; maybe was a typo.
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