Teledyne 3000MA Operating Instructions Manual page 27

Percent Oxygen Analyzer
Digital Remote Cal Inputs: Accept 0 V (off) or 24 V dc (on) inputs
for remote control of calibration. (See Remote Calibration Protocol below.)
Zero:
Span:
Cal Contact: This relay contact is closed while analyzer is spanning
and/or zeroing. (See Remote Calibration Protocol below.)
Remote Calibration Protocol: To properly time the Digital Remote
Cal Inputs to the Model 3000MA 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
2) When the CRC closes, remove the zero command.
3) When CRC opens again, send a span command until the CRC
4) When the CRC closes, remove the span command.
When CRC opens again, zero and span are done, and the sample is
being analyzed.
Floating input. A 5 to 24 V pulse input across the + and –
terminals puts the analyzer into the Zero mode. Either side
may be grounded at the source of the signal. A synchronous
signal must open and close the external zero valve appropri-
ately. See 3.3.3 Remote Probe Connector. (The –C option
internal valves operate automatically.)
Floating input. A 5 to 24 V pulse input across the + and –
terminals puts the analyzer into the Span mode. Either side
may be grounded at the source of the signal. A synchronous
signal must open and close external span valve appropriately.
See 3.3.3 Remote Probe Connector. (The –C option internal
valves operate automatically.)
until the CRC closes (The CRC will quickly close.)
closes. (The CRC will quickly close.)
Teledyne Analytical Instruments
Installation 3
3-7