Teledyne 2120XL - Trace Nitrogen Analyzer - Manual (Page 35)

Trace Nitrogen in Argon Analyzer Installation
Teledyne Analytical Instruments 23
Digital Remote Cal Inputs: Accept 0 V (off) or 24 VDC (on) inputs for
remote control of calibration. (See Remote Calibration Protocol below.)
See Table 3-3 for pin connections.
Zero: Floating input. 5 to 24 V input across the + and – pins
puts the analyzer into the Zero mode. Either side may be
grounded at the source of the signal. 0 to 1 volt across
the terminals allows Zero mode to terminate when done.
A synchronous signal must open and close the external
zero valve appropriately. See Remote Probe Connector.
Span: Floating input. 5 to 24 V input across the + and – pins
puts the analyzer into the Span mode. Either side may be
grounded at the source of the signal. 0 to 1 volt across
the terminals allows Span mode to terminate when done.
A synchronous signal must open and close external span
valve appropriately. See Figure 3-4 Remote Valve
Connections.
Cal Contact: This relay contact is closed while analyzer is spanning
and/or zeroing. (See Remote Calibration Protocol below.)
Table 3-3: Remote Calibration Connections
Pin Function
9 + Remote Zero
11 – Remote Zero
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 Model 2120XL 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 zero or span command can be sent.