ABB CM30 User Manual page 22

ControlMaster CM30 and CM50
Universal process controllers,
...Basic / ...Loop 1 (2) Control / ... Autotune
First Step
Dynamics
Normal
Deadtime
PI
Reset
PID
Proportional Band 1
Integral Time 1
Derivative Time 1
Manual Reset
FeedForward
Gain
20
1 1
/ and / DIN
4 2
Defines the maximum size of the first output step in the autotuning process. Autotune
adjusts the output step magnitude according to the process noise and response to provide
a reliable measurement of the process characteristics with the minimum disturbance of the
process. The maximum setting provides the largest output step possible from the current
output value.
Used to configure Autotune to give optimum results according to the type of process being
controlled.
Determines if derivative control is required automatically and calculates the control settings
accordingly.
Sets the proportional and integral terms to give optimum control for the deadtime process
(higher proportional band [lower gain] and shorter integration time).
Used for processes where it is known that derivative control is not required.
If the controller is transferred to another process or duty, Autotune must be reset. The
current PID (see below) settings are retained but the internal process data is cleared ready
for a completely new process with different characteristics.
The controller's PID settings can be commissioned using the Autotune (see page 19)
function and / or they can be adjusted manually. 3 Sets of parameters are provided to
facilitate Gain Scheduling control – see page 40. When Gain Scheduling is not enabled, the
first set of PID parameters only are used.
Set as % of engineering range.
Set in seconds per repeat. To turn integral action off, set to 0 or 10000 s.
Set in seconds.
When the Integral Time is Off, the manual reset parameter is activated. When the process
variable is equal to the control setpoint, the output value is equal to the manual reset value.
: The controller is shipped with null PID values (P=100, I=off & D=0). To enable the
Note
controller to control the process it is connected to, these values must be tuned accordingly.
This can be achieved via the AutoTune function or manual adjustment. If the controller is
tuned manually the table below provides details of some suggested values to start from.
These values are only suggested starting values and should not be used as an alternative to
proper tuning of the Controller.
Process Type
Temperature (fast)*
Temperature (slow)*
Pressure (fast)
Pressure (slow)
Level (fast)
Level (slow)
Flow
*For temperature loops, control performance can be improved via the use of Derivative. 
1
A suggested starting value is
Applicable only if a FeedForward application template is enabled – see Section 8, page 64
for template details.
Sets the gain to be used when in Static Gain mode – see page 42.
In Adaptive Gain mode this value is set automatically by the controller – see page 42.
P I
10 30
10 300
100 1
10 30
100 1
10 30
100 1
th
/ of the Integral value.
6
6 Basic Level
IM/CM/ED–EN Rev. B