Range Id Relays - Teledyne 2020 Operating Instructions Manual

3 Installation
priately. See 3.3.9 Remote Probe Connector. (With the –C
option, the internal valves operate automatically.)
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 2020 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.
When the contact is closed, the display would display the last reading
of the gas concentration value and output signal would output the last
reading from the sample gas (SAMPLE and HOLD).
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.
When CRC opens again, zero and span are done, and the sample is
being analyzed.
Note: The Remote Probe connector (paragraph 3.3.9) provides
signals to operate the zero and span gas valves synchro-
nously. However, if you have the –C Internal valve option,
which includes zero and span gas inputs, the 2020 automati-
cally regulates the zero, span and sample gas flow.

3.3.7 Range ID Relays

Four dedicated Range ID relay contacts. For any single application
they are assigned to relays in ascending order. For example: if all ranges
have the same application, then the lowest range is assigned to the Range 1
3-8
Teledyne Analytical Instruments
Model 2020