Model 979 Series Helium Mass Spectrometer Leak Detector
B-2
DRAFT 9/15/03
B.2 Communicating with RS-232
The RS232 Protocol is intended for diagnostic purposes and initial set-up inquires. The
RS232 connection is located on the rear D-sub 37 pin connector (refer to Table A-3 on
page A-4 and Figure A-4 on page A-4).
The 979 RS232 port is not an interrupt-driven port. It is configured as DTE (Data Terminal
Equipment), therefore the 979's RS232 Protocol cannot be sent as strings.
NOTE
When programming with virtual instrumentation programs such
as LabView, TestPoint, or Visual Basic, try one the following
two methods:
❑
The intended command must be transmitted one character
at a time with a minimal delay time of 50 milliseconds
between each character and terminating the command with
a carriage return (CR).
❑
The intended command must be transmitted one character
at a time, then wait for the echoed response from the 979
before transmitting the next character and then terminating
the command with a carriage return (CR).
Windows 95 and later versions contain a serial communications program called
HyperTerminal, a useful tool in establishing communication between the 979 and a PC.
B.2.1 Windows HyperTerminal Set-Up Instructions
To set up Windows HyperTerminal:
1. Click
Start
.
2. Select
Programs>Accessories>Communications>HyperTerminal
.
3. Double-click
Hypertrm.exe
.
The Connection Description dialog box appears.
4. Enter a name and choose an icon for the connection, for example: 979 RS232.
5. Click
OK
.
The Connect To dialog box appears.
6. Select a COM port from the
Connect Using
: the pull down list.
The Com Properties/Port Setting dialog box appears.
Summary of Contents for 979 Series
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