Ratio Station; Changing Controller Modes - ABB Command Series Instruction Manual

OPERATING PROCEDURES
Controller in AUTO
Controller in MAN
Controller in CAS
PROCESS DISPLAY
5 - 8
2. Use and to select the new control output. The value in the
s t
upper right hand corner of the display will show the values ramping
up or down and the CO bar graph will move right or left (up or down
on Type 2 display).
Changing Modes - Cascade Station
To change modes, perform the following procedures and refer to Fig-
ure 5-3.
1. To change to MAN, press
2. To change to CASCADE, press the left soft key (F1).
1. To change to AUTO, press
2. To change to CAS, press
the left soft key (F1).
1. To change to MAN, press
2. To change to AUTO, press the left soft key (F1).
A/M
MANUAL
Figure 5-3. Changing Controller Modes

RATIO STATION

If the controller is configured as a ratio station, it differs from a basic
and cascade station in that the set point is determined by a wild or
uncontrolled variable. The set point is calculated by multiplying the
uncontrolled variable by a predetermined multiplier. During ratio
operation, the multiplication constant for the process can be modified
through the set point raise/lower pushbuttons. Ratio multipliers can
range from 0.01 to 10.0. To adjust the set point (ratio index) and the
control output on a controller configured for ratio, use the following
procedures. Table 5-4 explains in which mode the controller needs to
.
A/M
.
A/M
to change to AUTO, then press
A/M
.
A/M
AUTO
F1
(LEFT SOFT
KEY)
F1
A/M
(LEFT SOFT
KEY)
CASCADE
OR
A/M
RATIO
TP80415A