ATI
Q45D/60 Dissolved Oxygen System
Part 5 – Configuration
O & M Manual
Revision C (7/09)
41 -
When the phase is LO, the relay energizes and the LCD
indicator illuminates when the oxygen level drops
below
the
setpoint. The failsafe setting does have an impact on this
logic. The description here assumes the failsafe setting is
OFF. Press ENTER to initiate user entry mode, and the
entire value will flash. Use the UP arrow key to modify the
desired value; selections include
HI
for direct operation or
LO
for reverse operation. Press ENTER to store the new
value.
See Figure 6-3 below for a visual description of a typical
control relay application.
Figure 5-3 Control Relay Example, Hysteresis and Two Opposite Phase Options
Setpoint: 1.000 ppm
Hyst:
0.050
Delay:
000
Failsafe: OFF
When value rises to
≥
1.000 ppm, relay closes.
When value falls to
≤
0.950 ppm, relay opens.
When value rises to
≥
1.050 ppm, relay opens.
When value falls to
≤
1.000 ppm, relay closes.
Settings:
}
1.000 ppm
0.950 ppm
PHASE: HI
ON
HYSTERESIS
OR
“DEAD BAND”
X
OFF
}
1.050 ppm
1.000 ppm
PHASE: LO
OFF
HYSTERESIS
OR
“DEAD BAND”
X
ON
