30
Controller 1
Controller 2
Set Point Tracking
(optional)
Master
RSP
LSP
PV
Slave
LSP
PV
P.I.D.
O/P
Software Link
Auto
CAS
P.I.D. O/P
Master
RSP
LSP
PV
Slave
CAS
LSP
PV
P.I.D.
O/P
Software Link
Auto
P.I.D. O/P
Master
RSP
LSP
PV
P.I.D.
O/P
Slave
CAS
LSP
PV
P.I.D.
O/P
Software Link
Auto
Auto
Slave Switched to
Manual Mode
Slave Switched to
Automatic Mode
Auto
Man
Cascade Set Point
Selected on Slave
Local Set Point
Selected on Slave
…4
CONTROL CONFIGURATION LEVEL
…4.1
Set Points
Information.
• Cascade control – comprises two series-connected controllers (master and slave), each containing a complete
measuring and controlling system operating on a single regulating device. Cascade control is only available when two
control front panels are fitted (channel 1 and channel 2) and channel 2 has no Remote set point facility. Channel 1 is the
‘Master’ controller and channel 2 is the ‘Slave’ controller.
• Cascade control with output tracking – ensures bumpless transfer when switching between auto/manual modes, i.e.
when the slave is switched to Manual it switches the Master to Manual, automatically .
• Cascade control with set point tracking – ensures bumpless transfer when switching between local/cascade set points
modes.
4.1.1
Cascade Control (without output tracking)
Full Automatic Cascade Control Mode
A ratio and bias can be applied to the
cascade set point (derived from the master
output) to give the required slave set point.
To switch to
Manual Mode
, press the
switch to select manual mode on the slave.
To switch to
Local Set Point Mode
, select
local set point in
Operating Page
of the slave.
Manual Mode
If the slave is switched from automatic
control to manual control, with cascade set
point selected, the set point type
automatically reverts to local, irrespective of
the output tracking setting.
Local Set Point Mode
If local set point is selected on the slave
when in
Full Automatic Cascade Mode,
operation of the master is not affected.
To return to
Full Automatic Cascade Mode:
Press the
switch to select automatic
mode on the slave and select cascade set
point in
Operating Page
of the slave.