VISA Resource Name conversion for Hex

[Dennis_Knutson]

All that a loopback test verifies is that the serial port on the pc is working. It certainly doesn't verify the cable because you need a straight-through cable to the instrument and a null-modem cable is required for a loopback test. According to the manual, you also have to turn communications on from the front panel. Have you done that? Verify that has been done and that you are using the correct cable.

[jesus.rp]

I used a straight through cable and connected pins 2/3 for the loopback test.  I used same cable to communicate with other hardware with no problems.  I'm sure it is the right cable.  Yes I enabled the serial communications on the RTE 17 whenever i attempted to use the .vi's provided. The continue to get same error.

-Jesus

[jesus.rp]

Sorry meant I used a Null cable.  pins 2/3 crossover.

-jesus

[Dennis_Knutson]

It really doesn't matter whether you used that cable with other equipment or not. The pc end has pin 2 as Rx and pin 3 ix Tx. Look at your manual. They label pin 2 as Tx and pin 3 as Rx. You have to connect Tx to Rx and that means you can't use a null modem cable.

[jesus.rp]

Indeed that was the communication problem i was having.  Like I said I'm new to LabVIEW, thus new to serial connections.  I was under impression there was only one standard type of communication where the cross-over was standard.

I had to change the port number (show control) and the baud rate to match what was default from the device in order for it to work though.  I don't have the serial error anymore from LabVIEW, but I do get an error on the device every time I send a command. 

Operational Errors:
ER 15 -- Asynchronous communication error, check serial interface parameters

Any command i send gives me this error on the device immediately.  Some commands work and device sends me correct info, even after the error.  Can you guide me what usually causes "Asynchronous errors"?  The Set Set Point command does not work, but most read commands do, after the error.

-jesus

[RavensFan]

Is that error showing up on your device, or in LabVIEW?  I would guess that it is showing up on your device.

Check your baud rate and data bits (usually either 7 or 8), stop bits (1, 1.5, or 2) and parity (none, even, odd, space, or mark, but usually one of the first three).

[jesus.rp]

Well once i was able to communicate with the device, I could work out the bugs.  Here's a list for anyone that has a use for this:

In the RTE-17.vi, set the port control I32 from hidden to show and change it as necessary (default =0).
In the Binary Serial Read.vi change baud rate as necessary (factory preset = 19200).
Make sure the res of the RTE17 is set at 0.01 (factory preset = 0.1). (pg 21 in manual)   ...Don't ask how i found that out but it involved looking at checksums and hex all day...

Thank you for your help.  Your time/help/patience has been very valuable.

-jesus

[jesus.rp]

Any other ideas as to why I would have the RTE 17 giving me this error:

Operational Errors:
ER 15 -- Asynchronous communication error, check serial interface parameters

I have the RTE 17 communications set to RS-232, Baud rate = 19200.  As a test i changed both the LabVIEW VI and the RTE 17 to 9600 but that didn't help either.  Any suggestions?  Could it be the various timings in the loops that read/write in the chiller.vi?

Attached is a vi i'm using for a calibration routine in conjunction with the RTE 17 library files. The goal I have is to change the temperature set point (RTE-17) then begin resistance measurements (other device)  along with internal temperature measurements (RTE 17).  The error is throwing off the timing and slowing down measurements so i need help correcting this.  Thanks.

-Jesus

ps.  Also if you know of a way of making my vi better please don't hesitate to respond...like i said i'm new to LabVIEW and any insight would be highly appreciated.


Message Edited by jesus.rp on 05-23-2008 07:20 PM

[Sputnikrent]

You mentioned in your previous post that you were able to get communications going with the device. What changed between now and previously that you receive that error message again?

Also, is this error happening on your device? At which point does the error occur?

[jesus.rp]

There is a timeout limit in the "chiller binary read.vi" subvi that causes the problem.  If I set the timeout value to 0 then the communication doesn't come back with errors on the device.

I did that and the files now work (no errors).  Just a quick clarification on these types of errros: if ever there is asychronous errors from a serial device this stems from the handshaking commands?  ie. baud rate, parity, etc...or can it come from eleswhere? 

-Jesus