I'm working on a system to log data from a cleanroom facility. I'm
developing with LabVIEW 8.5 on a WinXP PC and targeting a cFP-2100.
Both the PC and the cFP have FieldPoint 6.0 and NI-VISA 4.2 installed.
One of the devices I'm logging from is a MetOne A2408 laser prticle
counter system. The interface is via RS-232 over a 9 pin serial
cable. I'm using the VISA serial interface to communicate between the
MetOne and LabVIEW. RS-232 parameters are 9600-8-N-1 with no flow
control.
Everything works perfectly when I run the system on the PC, connecting
to the MetOne via the PC's COM1 port. Most of the commands to the
MetOne are a single character, and the reply is a few characters (<
10). The exception is the response to a request for a sample record
from the MetOne (that's the data I want to log). It's a 78 byte
string; typical example:
A 022008 120212 0057 0.5 105003 5.0 000158 FLO 000000 LOC 000017 C/S 000C24
(The 78 bytes includes a CRLF on the end, for anyone whose counting
🙂
My problem arises when I deploy the system to the cFP-2100 and use
its COM1 port. The commands to the MetOne work fine, and short
response strings come back fine, but the 78 byte string of sample data
comes back partially garbled, for example:
A
<<228<<<12<<468<<578<.5<1<58<385.8<<<<15<<FLO8<88<918LOC<<<<<178C/S8<<<C33
Š
(The line breaks are there in the string, though not always in the same
places.) I've checked and re-checked baud rate, parity, etc. If any
of those are set incorrectly, I have no communication between the cFP
and the MetOne. It's just the long string that gets messed up. The
<10 byte responses are always fine.
I've stripped the cable down to its bare essentials (pins 2 and 3 only) thinking that perhaps there is a noise issue. No help.
Any suggestions are welcome. I've run out of ideas...
Doug Latornell
MDS Nordion, Vancouver
