Teledyne 7120 Operating Instructions Manual page 19

Photometric Analyzer
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.
Note: The Remote Probe connector provides signals to operate the
zero and span gas valves synchronously. However, if you
have the –C Internal valve option, which includes zero and
span gas inputs, the 7120 automatically regulates the zero,
span and sample gas flow.
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 ID relay,
and the highest range is assigned to the Range 3 ID relay. Range 4 is the Cal
Range ID relay. Table 2-7 lists the pin connections.
closes. (The CRC will close quickly.)
2.3.3.4 Range ID Relays
RANGE 1
ID
CONTACT
Table 2-7: Range ID Relay Connections
Pin Function
21 Range 1 ID Contact
38 Range 1 ID Contact
22 Range 2 ID Contact
Teledyne Analytical Instruments
Moving contact
Normally
open
Installation 2
2-11