33 Glossary
98
Proportional
band
Pb
The range over which the output signal from a pulse width or
pulse frequency controller is proportional to the control
deviation. Beyond the proportional band, the controller will
output the signal defined by the
output level limit Y1 or Y2
.
Proportional
controller
C211
C213
C214
In a proportional controller there is a continuous signal (i.e. a
current or voltage) on the output. This signal can take on any
intermediate value between a start value and an end value.
Depending on the configuration of the instrument, this
continuous signal can be in the range 0 — 10 V, 0 — 20 mA or
4 — 20 mA.
Proportional controllers are used, for example, to operate
actuator valves.
Pulse contact /
steady contact
C213
The behavior of an alarm contact.
Pulse contact:
The alarm output remains active for approx. 1 second, even if
the switching condition (cause) of the alarm remains present for
a longer time.
The LED (for the output that was defined as the alarm output)
blinks until the switching condition (the cause) of the alarm is no
longer present.
Steady contact:
The alarm output remains active until the switching condition
(the cause) of the alarm is no longer present.
The LED blinks for the output that was defined as the alarm
output.
Pulse period
CY
This value is the period within which the pulse width modulation
occurs (only for a pulse width or modulating controller).
The value is limited by the
minimum ON time tr
, see above:
Pulse period [sec]> minimum ON time [sec])
Reset time
rt
Integral time constant – controller parameter in a PI or PID
controller. The value determines the speed at which the control
deviation is integrated. If the reset time is set to “0”, then the
control action has no integral component.
Setpoint 1
SP(r)1
The given value that should be achieved by the control loop
(referring to output K1).
The setpoint pair that is fed to the controller is identified in the
parameter display by (r). See also
Setpoint changeover
Example
for the active setpoint pair 1 => SPr1, SPr2 and SP 3, SP 4.
for the active setpoint pair 2 => SP 1, SP 2 and SPr3, SPr4.
Setpoint 2
SP(r)2
As for
setpoint 1
, referring to output K2
Setpoint 3
SP(r)3
Refers to output K1. For explanation see
Setpoint 1
.
Only with activated
setpoint changeover
Term
Parameter
Explanation
