Teledyne 7120 - NDIR analyzer - Manual (Page 17)

Photometric Analyzer Installation 2
2-9 Teledyne Analytical Instruments
Figure 2-4: Alarm Relay Contact Pins
THRESHOLD
ALARM 1
Press here to
insert wire.
Release to hold.
Insert wire
here.
Moving contact
Normally open
Normally closed
Remote Calibration Protocol: To properly time the Digital Remote
Cal Inputs to the Model 7120 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.
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 zero or span command is sent, and acknowledged (contact
closes), release it. If the command is continued until after the zero or span is
complete, the calibration will repeat and the Cal Relay Contact (CRC) will
close again.
For example:
1) Test the CRC. When the CRC is open, Send a zero command
until the CRC closes (The CRC will close quickly.)
2) When the CRC closes, remove the zero command.
3) When CRC opens again, send a span command until the CRC
closes. (The CRC will close quickly.)
4) When the CRC closes, remove the span command.