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Problems Communicating with device over VISA



I hope to give a thorough explanation with supplemental visual material to which someone might be able to provide insight and a helpful solution to my problem. To start, I have two 3-axis compass modules in which I am trying view the compass Heading, Pitch, and Roll for each. The first compass module is a Honeywell HMR3000 model in which I have modified the "Advanced Serial Write and" example VI to suit my needs and works properly. The HMR3000 picture (attached) shows the front panel and the output read string. I was able to add a "Scan to String" for the Heading, Pitch, and Roll to extract the data to an indicator. You can see this in the Bock Diagram picture (attached). Because of the application of which the compass will be used, I am unable to use the Honeywell 3000 compass module (due to range limits) and so I purchased the Honeywell HMR3500 module (due to a higher limit ranges on the Pitch and Roll). When using the same VI and changing the baud rate (and any other parameters) to match the compass device and running the VI, the output read string shows crazy characters. Please see HMR3500 picture for reference. I do not know if this is a serial communication issue or if the device is outputting in a different format (such as hexidecimal) than the HMR3000 compass. I do know that the HMR3000 serial communication is goverened by a asynchronous ASCII protocal modeled after the NMEA 0183 standard. Is there anyway I can output the HMR3500 in the same format? Any information or insight would be greatly appreciated. Thank you.  

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Message 1 of 7

The format of the data and the transmission options should be explained in the manual for the new device. If you need help in understanding what is there, you need to attach it.

Message 2 of 7

Below, I have attached the HMR3000 and HMR3500 manuals. Maybe I am just not understanding the output format of the HMR3500 correctly.

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Message 3 of 7

It's hex format though it states that the DPOWER message is readable text. Change the indicator to Hex Display.


Also, sending *IDN? is not correct since that is not a supported command.

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Message 4 of 7

Yes you are getting binary data.  Look at page 6-7 of the 3500 manual.


What you will need to do is break apart the appropriate bytes and typecast them to the appropriate datatype.

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Message 5 of 7

 I changed the string indicator to hex display. Now I am able to view the hex output.

What is the appropriate way to break apart the bytes and typecast them?

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Message 6 of 7

Try String to Byte Array.

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Message 7 of 7