Teledyne GC-Pro/TCD - Gas Chromatograph - Manual (Page 38)

Installation GC-ProTCD
Teledyne Analytical Instruments 24
3.3.2.6 D IGITAL R EMOTE C AL I NPUTS
The digital remote calibration signals are available on the bottom
connector. They input accepts 0 V (off) or 24 VDC (on) for remote
control of calibration. (See Remote Calibration Protocol below.) See
Table 3-4 for pin connections.
Span: Floating input. A 5–24 V input across the + and – pins puts the
analyzer into the Span mode If cycle mode is ‘Continuous’. Either
side may be grounded at the source of the signal. A 0–1 volt across
the terminals allows Span mode to terminate when done. A
synchronous signal must open and close external span valve
appropriately.
Cal Contact: This relay contact is closed while analyzer is spanning.
(See Remote Calibration Protocol below.)
Table 3-4: Remote Calibration Connections — Bottom Connector
Pin Function
10 + Remote Span
12 – Remote Span
40 Cal Contact
41 Cal Contact
Remote Calibration Protocol: To properly time the Digital Remote Cal
Inputs to the GC-Pro TCD Analyzer, the customer's controller must
monitor the Cal Relay Contact.
When the contact is OPEN, the analyzer is analyzing, the
Remote Cal Inputs are being polled, and a span command can be
sent.
When the contact is CLOSED, the analyzer is already calibrating. It
will ignore your request to calibrate, and it will not remember that
request.
Once a span command is sent, and acknowledged (contact closes),
release it. If the command is continued until after the span is complete,
the calibration will repeat and the Cal Relay Contact (CRC) will close
again.
For example: