MANUAL P/N 316005 REV: B
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Talk-Only Mode
Switch #8, if set to OFF at power-up, puts the interface in Talk-Only mode. The pressure data from all three
displays will be output in a single message string, separated by commas, approximately every 5 seconds.
When shipped from the factory, the Talk-Only mode is disabled.
SRQ Mode
Switch #7, if set to OFF at power-up, tells the interface to generate an SRQ interrupt and respond to a serial
poll with a message output.
The serial poll response byte will contain a 1 in bit 6 (the second-highest bit). Bit 5 will be set if an error has
occurred. In this case the pending message will be an error message. When shipped from the factory, SRQ
mode is disabled.
7.3 IEEE 488 Operation
Communication with the 316 is via ASCII strings. A message to the 316 consists of a command and a
command modifier, followed by a terminator. The message can contain leading spaces, and the command
and modifier can optionally be separated by spaces or commas. No spaces may appear within the command
or the modifier, only between them.
The terminator accepted by the 316 is an ASCII carriage return line feed, denoted here by CRLF. The
carriage return is optional, and messages terminated with only the line feed will be accepted. Note that the
CRLF terminator is in general appended automatically, by the host computer's interface software, to the
message string supplied by the user.
A terminator is not required, if the last character of the message to the 316 VGC is accompanied by the EOI
bus signal.
If extra characters are found in the message after it has been successfully interpreted but before the
terminator, they will be ignored.
All characters should be upper-case.
All messages to the 316 will receive a reply consisting of an ASCII string terminated with CRLF, the LF being
accompanied by EOI. Pressure data will be returned in scientific notation with the format X.XXE±XX.
7.3.1 Command Syntax
DS
Definition:
Display pressure reading.
Modifiers:
CG1 or CG2 or CG3 or 1 or 2 or 3.
Response:
ASCII string representing the pressure for the selected gauge.
Example:
From computer: DS CG1 CRLF
From 316: 1.20E-03CRLF
NOTES
1.
The DS CG1, DS CG2 and DS CG3 commands or DS1, DS2, and DS3 commands are used to
display the pressures from the A. B and C display lines, respectively, with either the Convectron ,
Thermocouple, or Capacitance Manometer Gauge Module installed.
2.
If data is requested from a Convectron , Thermocouple, or Capacitance Manometer Gauge when
none is installed, the 316 will return 9.99E+09.
