Teledyne 3290 - OEM percent oxygen analyzer - Manual (Page 29)

Percent Oxygen Analyzer Installation
Teledyne Analytical Instruments 19
CAUTION: INSERT THE STRIPPED TIPS OF WIRES ENTIRELY
INTO THE TERMINAL BLOCKS. DO NOT LEAVE
EXPOSED WIRE OUTSIDE OF THE HOLES IN THE
BLOCKS.
CAUTION: THE CONTROL UNIT CHASSIS MUST BE ISOLATED
FROM THE GROUNDING SYSTEM OF THE DC INPUT
POWER.
Analog Outputs: There are three DC output signal connectors with
screw terminals on the panel. There are two wires per output with the
polarity noted. See Figure 3-1. The outputs are:
0–10 V % Range:
Voltage rises with increasing oxygen
concentration, from 0 V at 0 percent oxygen to 10
V at full scale percent oxygen. (Full scale = 100%
of programmed range.)
0–10 V Range ID: 3.33 V = Low Range, 6.66 V = High Range,
10 V = Air Cal Range.
4–20 mA % Range: Current increases with increasing oxygen
concentration, from 4 mA at 0 percent oxygen to
20 mA at full scale percent oxygen. (Full scale =
100% of programmed range.)
Alarm Relays: The three alarm-circuit connectors are screw
terminals for making connections to internal alarm relay contacts. There
is one set of contacts for each type of alarm. Contacts are Form C, with
normally open and normally closed contact connections capable of
switching up to 0.5 ampere at 125 VAC into a resistive load.
The alarm relay circuits are designed for failsafe operation,
meaning the relays are energized during normal operation. If power fails
the relays de-energize (alarms activated).
The contact connections are indicated diagrammatically on the rear
panel as Normally Closed, Common, and Normally Open. Figure 3-2
explains how these act in failsafe operation.