Lakeshore Transmitter 240-2P is not accessible through USB

msrajpoot
New Member

Posts: 2

Lakeshore Transmitter 240-2P is not accessible through USB Feb 5, 2018 4:21:09 GMT -5

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Post by msrajpoot on Feb 5, 2018 4:21:09 GMT -5

Dear Experts,
I am facing following problem while trying to access Lakeshore temperature transmitter 240-2P via USB suing measurelink software:
1. I have two transmitters of same type (240-2P) wherein one is accessible through both USB and Profibus connection. But other one is not getting accessed via USB but its also getting accessed through profibus connections.
2. I observed that in this transmitter(which is not accessible via USB), a steady red communication LED is glowing during power ON state but in other transmitter which is accessible via USB, this communication LED is flashing red and after connecting to profibus master, Its steady green showing successful communication and data exchange.
3. While accessing through profibus, I am able to view that the pre-setted profibus address is 126, but to change this address to correct one, I am not able to access this transmitter via USB (see the attached screeshot).
4. Once, I try to connect via USB, the USB connection is not getting detected in the computer and also not in the measurelink software. But for other transmitter, system immediately detects the USB connection and it appears under the correct COM port on Measurelink software and I am able to connect and successfully do parameterisation for it.
5. From point no. 4 above, its obvious that I have installed the USB driver and MeasureLink software correctly as one transmitter is getting accessed via USB but other one is not.
Kindly look into the same and suggest me the remedial action to resolve this problem.

Thanks you in advance.

Lake Shore Jeff M
Lake Shore

Posts: 327

Lakeshore Transmitter 240-2P is not accessible through USB Feb 5, 2018 8:28:08 GMT -5

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Post by Lake Shore Jeff M on Feb 5, 2018 8:28:08 GMT -5

Hello msrajpoot,

Regretfully, it sounds like your Model 240-2P has a defective USB Interface device on the circuit board and will need to be repaired or replaced. Please send the following information to service@lakeshore.com:

Your full given name

Name of the company or educational institute you represent

Address of the above including:

Street,

City

State or region

Postal Code

Country of not the US

Your contact telephone number

Once we receive your information, we will determine the warranty status and let you know how we will proceed with the resolution.

msrajpoot
New Member

Posts: 2

Lakeshore Transmitter 240-2P is not accessible through USB Feb 12, 2018 8:42:12 GMT -5

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Post by msrajpoot on Feb 12, 2018 8:42:12 GMT -5

Dear Jeff M,
Thanks for your reply. I will send the requested details.
Meanwhile, I need one more help. With one 240-2P which is successfully communicated, I am getting four process image bytes (PIB-1, PIB-2, PIB-3 and PIB-4) for each sensor reading module in Siemens STEP7 Hardware configuration as Profibus DP slave.
Can you please guide me, on which input byte address it will give me temperature reading of connected RTD sensor? or how can I decode reading being received on above address input bytes?

Lake Shore Jeff M
Lake Shore

Posts: 327

Lakeshore Transmitter 240-2P is not accessible through USB Feb 12, 2018 12:11:10 GMT -5

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Post by Lake Shore Jeff M on Feb 12, 2018 12:11:10 GMT -5

msrajpoot,

I think I understand what you are saying, however, to make sure I understand correctly here are my assumptions:

It sounds like you are getting back four bytes from each sensor reading. I’m assuming that the PIB is a single byte. The Siemens software needs to be setup to accept that in as a single, four-byte value that is then interoperated as a floating point value. That should start to give you good floating point readings.

Next, you should use MeasureLINK to setup what data you are sending back to the PLC and this is where you can choose to send the temperature reading (K or C) instead of a sensor reading (ohms). I think your biggest issue is bringing those four bytes in as one word and converting it to a floating point number.