Paroscientific Model745,rs232 communication problem

[yimusan]

Im trying to use LabView to communicate to the Paroscientific Model745 .  Im using the basic serial write and read structure . When I send a request for pressure (as *0100P1) I cant get a response from the device.  If I use the the Paroscientifc software it works fine.  Any tricks to getting the LabView software to communicate?

there is a pidture of block diagram

Thanks a lot!

[yimusan]

Im trying to use LabView to communicate to the Paroscientific Model745 .  Im using the basic serial write and read structure . When I send a request for pressure (as *0100P1) I cant get a response from the device.  If I use the the Paroscientifc software it works fine.  Any tricks to getting the LabView software to communicate?

there is a pidture of block diagram

Thanks a lot!

[yimusan]

Im trying to use LabView to communicate to the Paroscientific Model745 .  Im using the basic serial write and read structure . When I send a request for pressure (as *0100P1) I cant get a response from the device.  If I use the the Paroscientifc software it works fine.  Any tricks to getting the LabView software to communicate?

there is a pidture of block diagram

Thanks a lot!

[Dagaror]

Hi Yimusan,

how do you communicate with the instruments, GPIB? USB?

I advise you to initiate from a LabVIEW example that you can find in the example finder of LabVIEW.

Help>>Find Examples...

In order to understand how the packet information is send, why don't to sniff the communication? 

Serial Port Forwarding (Port Sniffer/Logger)

https://decibel.ni.com/content/docs/DOC-5673

I also attach the NI-VISA™User Manual.

http://www.ni.com/pdf/manuals/321074a.pdf

Good luck with your communication!

[JÞB]

Well that model actually has a deterministic serial protocol.  All messages end with a \cr\lf so set the term character to 0x10 and read 100 bytes.  Bytes at port is not the prefered method of figuring out how many charaters to read.

Moreover the *01001P command initiates a reading (which will take some finite amount of to to process)  Bytes at port placed directly after the write will almost always be 0 since the pressure measurement hasn't yet been made.

[crossrulz]

What exactly are you sending to the instrument?

From looking at the manual (http://www.paroscientific.com/manuals/8004-001.pdf), you should just be using the termination character to stop your VISA Read.  You are already configured to use the termination character.  So all you need to do is remove the Bytes At Port property node and wire in something like 50 to the Bytes To Read in the VISA Read.  The VISA Read will stop reading when the number of bytes to read are read or when the termination character is found, whichever happens first.

[yimusan]

thaks a lot! I used the rs232 which is an USB.

I have already tried the LABVIEW examples ,and there is still no response when I send the command *0100P1.Moreover,when I send the command like *IDN?\n,I can get the same *IDN?\n as response in the reading string field.

[Dennis_Knutson]

Why would you send *IDN?. It's not in the manual.

What are you appending to the command? Is it \r\n and is your string control set for \ Codes Display (right click option)?