Appendix D Pid Control; Operator Pages; Reverse Or Direct-Acting Control; Dual-Acting (Acid And Base) Control - ABB AWT420 Operating Instruction

104 AW T4 2 0 | U N I V E R S A L 4 - W I R E , D U A L- I N P U T T R A N S M I T T E R | O I/A W T4 2 0 - E N R E V. B

Appendix D PID control

Enables simple PID control of pH and conductivity sensor
channels (control of other signals [turbidity, dissolved oxygen
etc.] is not required).
Control functionality is available for both channels of the
AWT420 transmitter.
Conductivity channels are configurable for reverse or direct-
acting control. pH channels are configurable for reverse-acting,
direct-acting or dual (Acid/Base) control:
• a reverse-acting controller generates a single control
output
• a direct-acting controller generates a single control output
• a dual-acting controller generates 2 control outputs
Control outputs are configurable for Analog, Time
Proportioning or Pulse Frequency output. Analog control
outputs can be assigned to any of the available analog outputs.
Time proportioning control outputs can be assigned to any
of the available relays or digital outputs and pulse frequency
control outputs can be assigned to any of the available relays
or digital outputs.

Operator pages

Reverse or direct-acting control

Device Tag
Sensor Tag
PV
SP
O/P
A
Instrument tag
B
Sensor-specific tag
C
Primary value and units
D
Adjustable parameter icon (using
E
Setpoint
F
Control output percentage
G
Status bar icons – see page 35
H
Diagnostic icon/diagnostic message – see page 83
I
Icon: Auto/Manual control – see page 35
J
Time and date
Figure 35 Operator page – reverse or direct-acting control

Dual-acting (Acid and Base) control

Device Tag
Sensor Tag
PV
SPA
8.00
O/P
A
Instrument tag
B
Sensor-specific tag
C
Primary Value & units
D
SPA: Acid control setpoint.
E
SPB: Base control setpoint
F
Control output percentage
G
Status bar icons – see page 35
H
Diagnostic icon/diagnostic message – see page 83
I
Icon: Auto/Manual control – see page 35
J
Adjustable parameter icon (using
K
Time and date
Figure 36 Operator page – dual-acting (Acid and Base) control
04-09-2019
08:52:03
3.50
PV unit
7.00
65.0
%
S1: Recovery
CAL
/
/
keys).
04-09-2019
08:52:03
13.50
PV unit
SPA
6.00
–50.0
%
S1: Recovery
CAL L
/
/
keys).