3-3
Flue Gas Analysis System Installation 3
TELEDYNE BROWN ENGINEERING
Analytical Instruments
3.1.3 Alarm and/or Control Circuitry
Models having a -1 or -2 as part of their model number are equipped
with single (-1) or double (-2) alarm and/or control circuits.
The SPDT form "C" (NC/C/NO) contacts of the relay (or relays) are
available on the terminal strip within the oxygen analyzer. To properly use
the switch that the relay contacts represent, the customer must determine
when the relay (or relays) is energized (above or below the setpoint). The
appropriate terminal strip connections are identified on the interconnection
diagram (see Figure 6).
For those not familiar with relay terminology, the terms normally
open (NO) and normally closed (NC) refer to the relay contact configura-
tion when the relay is in a de-energized condition.
The load current per relay must be limited to 3 Amperes non-induc-
tive.
3.1.4 Output Signal Current
Instruments which include the designation "I" as part of their model
number are equipped with an E-to-I converter to provide a DC milliampere
(mA) output signal as well as a DC voltage signal.
A separate 1/4 ampere slow-blow fuse, located on the analyzer control
panel, protects this circuitry.
The range for current output is:
• 4–20 mA dc
Suitable for devices with 0–1500 Ohms impedance
(resistive).
The appropriate terminal strip connections are identified on the
interconnection diagram (see Figure 6).