Bad data from 485 serail read...

[teslac]

    I have a Watlow EZ-PM controller connected on a 485 serial bus and I can write commands to the controller with out issue however, when I try to read a temperature back the data does not make any sence.  In the screen shot bellow is the read frame with probes on the read out(4), the hi/low out (2) and the cast type.  I have looked at examples and and in comparison they all do the same.  I also tried using the Labview modbus serial tools for read and it produced the same results.  I am having trouble finding a new direction and any suggestions would be a geat help.

[Dennis_Knutson]

Are you sure of the byte order? If you swap them, doors the reading make more sense? What are those subVIs? Are they from the driver at http://sine.ni.com/apps/utf8/niid_web_display.download_page?p_id_guid=78A7BD5105DA2303E04400144FB7D2...

[teslac]

    I tried to swap the order and the data still made no sence just the sine of the exponet.  The vis are from the Saphire tool for modbus over serial.  The unusual thing is that I tried to do the same opperation with the free Labview modus tool and I got exactly the same numbers back.  I have also talked to Watlow about this and they are blaming the code.

[mikeporter]

Any idea what the data is supposed to be? For grins, I tried swapping words, bytes within words, and swapped both word and byte order. All the results were either really big or really small. I even tried reversing the bit order in the individual words.

Are you sure you have the comm parameters right?

Mike...

[teslac]

    The numbers read back from the TC is suppose to be aroud room temp or 22 C which is what the controller is reading.  As for the comm settings the controller does not give you a lot of options in its setup but Modbus and lo/hi-hi/lo.  I checked the other serial settings for the code and they are as perscibed.

[Matthew_Kelton]

Looking at the manual, the temperature is in 360 and 361, but it looks like you're looking at 361 and 362.

The manual also states the words are in low/high order, so you would need to swap the words before you build the U32.  The example they give gives a slightly different answer than I get by two other sources, but it should be in the right ballpark.

https://www.instrumart.com/assets/ezzone-pm_communicationsmanual.pdf

Page 14

[teslac]

    I have changed the order on the controller from lo/hi to hi/lo recently however, in a previous effort I did reverse the array when it was set as factory.  I also put in the temp address as 360 and 361 with the same results.