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VISA serial connectivity issue using USB to RS232 port

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Hello all,

 

I am working on a project to automate a Createc power supply by using labVIEW. I have a USB to RS232 adapter to communicate between the USB port on my laptop and the RS232 port on the power supply. 

 

We set up a more controlled experiment for my labVIEW program by disconnecting the evaporator and instead shorting the wires that would normally go to the evaporator. We also reduced the maximum amp output of the power supply, and connected a heat dispersion component to the circuit. Lastly, we connected up a thermocouple as the input, so that when we touch it with out hand, it heats up and sends some information through the power supply to my computer. 

 

Given this experiment, and the most basic VI I could create, there is no output to the waveform graph. There are no errors, but there is no information being sent to the waveform graph. In terms of the pinout of the RS232 cable, the manual only says there are pins for transmitting, receiving, and common ground, but it does not say what transmitting and receiving mean. Does anyone older and wiser than myself have insight into this problem? Thank you

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@Josh_Music wrote:

Hello all,

 

I am working on a project to automate a Createc power supply by using labVIEW. I have a USB to RS232 adapter to communicate between the USB port on my laptop and the RS232 port on the power supply. 

 

We set up a more controlled experiment for my labVIEW program by disconnecting the evaporator and instead shorting the wires that would normally go to the evaporator. We also reduced the maximum amp output of the power supply, and connected a heat dispersion component to the circuit. Lastly, we connected up a thermocouple as the input, so that when we touch it with out hand, it heats up and sends some information through the power supply to my computer. 

 

Given this experiment, and the most basic VI I could create, there is no output to the waveform graph. There are no errors, but there is no information being sent to the waveform graph. In terms of the pinout of the RS232 cable, the manual only says there are pins for transmitting, receiving, and common ground, but it does not say what transmitting and receiving mean. Does anyone older and wiser than myself have insight into this problem? Thank you


Well RS-232 is an industry standard your USB-RS232 converter RS232 side is probably 9 male pins and should be wired as DTE. (Data Terminal Equipment)

 

Also are you receiving any data? (I can't open your program because I only have LV2020 here)

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=== Engineer Ambiguously ===
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Here lies the issue- I am not receiving any data. At least no data is transmitted to the waveform graph. I have attached an older version of VI. So are you saying its not necessary to configure any signal from the power supply? Can I simply use labVIEW VISA serial components to produce a signal? Thank you very much and I apologize for any unprofessional or unexperienced questions, as I still have much to learn. 

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@Josh_Music wrote:

Here lies the issue- I am not receiving any data. At least no data is transmitted to the waveform graph. I have attached an older version of VI. So are you saying its not necessary to configure any signal from the power supply? Can I simply use labVIEW VISA serial components to produce a signal? Thank you very much and I apologize for any unprofessional or unexperienced questions, as I still have much to learn. 


I suggest you watch this video: VIWeek 2020/Proper way to communicate over serial

 

It will probably answer your questions.

 

I see you are using the Configure Serial defaults (9600 baud 8 bits 1 stop bit) is that correct for your instrument?

 

Some instruments need to be put in remote control mode manually.

 

You are writing a "1" with no "carriage return" or "new line"  termination character. Is that correct for your instrument?

 

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=== Engineer Ambiguously ===
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Do you have a link to the manual or something for us to verify the communication and message protocol?


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here is a compressed version of the manual. 

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Solution
Accepted by topic author Josh_Music

I think you really need to read that manual because just a quick skim found this:

 

DC.PNG

 

It would appear to me that this device uses Modbus. So standard serial communications using VISA read and write is probably not going to work unless you really want to dig that deep into Modbus and reinvent the wheel.

 

There is a free Modbus library for LabVIEW  that handles the "hairy details" of the Modbus protocol  

 

Also...

14Capture.PNG

These are the default serial settings not 9600 baud...

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=== Engineer Ambiguously ===
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