fluke hydra 2635a serial port communication

[Christian S.]

Hello,
I am trying to communicate with a Fluke Hydra 2635a but I have no success. The generic software is able to pull data so the connection and port selection is fine. Nevertheless, based on LabView's serial vi's I cannot establish a connection.
Thanks for your help.

Christian

[Dennis_Knutson]

What happens when you try to talk to it? Do you get an error? What error? Are you using one of the shipping examples? Which one? Are you sending the correct termination character? Are you using VISA? What version of LabVIEW are you using?

Some of the most common mistakes made when using any of the shipping examples is incorrectly specifying the com parameters (baud rate, etc) and not appending a termination character at the end of the write string. A termination character is usually either a CR or LF (check your manual). One way to send a term character is to turn on '\' Codes Display in the front panel string control. You get this option when you right click on the control. Then type your command followed by either a \n (line feed) or \r (carriage return). If that doesn't work and you've double checked the com settings, answer the questions above and post an example of the code you've written.

[Christian S.]

Thanks for your reply.
First of all I am using LabView 6.1. I get an error 37 in the moment when I use "serial port init.vi" (In this case I am not using Visa). The com settings are 9600baud, data bits 8, stop bits 1 and no parity as mentioned in the instrument manual.
When I use a communication panel in measurement and automation explorer I can talk to the device. In this case it is Visa. If I use the LabView example "LabView <-> Serial.vi" (Visa again) just nothing happens.
I am a bit confused since I think what I try to do is very basic.

Thanks
Christian

[Dennis_Knutson]

First, I would recomend that you only use the VISA functions. The old serial driver is obsolete and no longer supported by NI. The error 37 means Device Not Found I think. One of the goofy things about the old serial driver was that for com1, you to specify port 0, com2 was port 1, etc. If you only have one com port and you use port 1, that could cause the error. Since you can talk to the instrument in MAX, then stick with the VISA functions. When you try the example and you say nothing happens, do you get an error generated or does the instrument just not respond? Are you sending a command or a query?

The first thing you do with the example is click on the little arrow on the right side of the VISA Resource Name. A list of all available resources should show up. Select the com port that your instrument is connected to. Second, right click on the String to Write control and select '\' Codes Display. As I mentioned, the example does not transmit a termination character. I looked at the driver for the Fluke 2620 and it is sending a CR/LF. In the String To Write control enter *IDN?\r\n. Run the VI with both Write and Read set to On and a small value for the Bytes to Read. If you get soemthing at all in the Read String indicator, then you're close. If you don't get anything, you should get something in the error indicator.

[Christian S.]

Yeah, things start to work out...
but a new problem is arising. I want to use an edgeport usb expansion module such that I have multiple com ports. Unfortunately, in the moment where I plug my fluke reader into the expansion module I cannot communicate anymore. For example, if I plug it in port 1 of the module, which corresponds to com4 according to the module configuration, it just does not respond.
Any idea?

Thanks
Christian

[JohnM 64]

Hi Christian,

Just to make sure we're all on the same page, I want to make sure that you were able to follow Dennis's great advice and were able to communicate with your device through LabVIEW using the built in serial port on your device. If we are not able to get this to work, then there is no sense in trying to make it work through the USB extender.

Generally, these USB to serial devices require some type of driver to be installed in order for the COM ports to be available. Once the driver is installed, when you plug in the device, the extra COM ports should show up in Device Manager, and then also should show up in MAX. Once they show up in MAX, I recommend opening a VISA session to COM4 through MAX to make sure you can communicate that way. From there, follow the directions in Dennis's previous post, only select COM4 from the drop-down menu for the VISA Resource Name.

Hope this helps!

john