Siemens SIMATIC S5 Manual page 323

Secondary control loop
Self-tuning
Setpoint jump (step)
Setpoint ramping
Setpoints
Software release
Special function
Status (byte)
Symmetrical/asymmetrical
controlled systems
System deviation x
d
T
A
T
D
Temperature compensation
Thermocouple
Three-step controller
Three-wire connection
T
N
Tolerance values
Transfer RAM
Two-step controller
IP244
C79000–Y8576–C858–02
Secondary control loop, whose setpoint is influenced by a master
controller in cascaded control.
Based on a mathematical quality criteria, the controller
parameters are matched to the existing task automatically to
achieve an optimum controller action.
Entry of a new setpoint with a value different from the old setpoint.
To damp setpoint jumps, the setpoint is not changed suddenly but
follows a selectable ramp slope.
Desired (demanded) process value to be maintained by the
controller.
Release of the operating program in the EPROM of the module.
Special mode which controls the read-in of measured values via
the channels 13 and 14 in a way, which makes it possible to
acquire series of measured values in curved form (channel 13)
and to allocate a measured value from channel 14.
Eight-bit information unit; each bit is assigned to a particular error
(1 = error).
If the measurement equipment (here, thermocouple) is arranged
symmetrically to the actuators for the heating or cooling, the
controlled system is symmetrical, otherwise it is asymmetrical
(e.g. extruder heating with unequally divided heating band and
thermocouple between).
Difference between the entered setpoint and measured actual
value (input variable of the controller).
Sampling time
Derivative action time (describes the D action).
When measuring temperatures with thermocouples, the voltage
produced by the thermocouple is proportional to the temperature
difference between the measuring junction and the reference
junction. The temperature compensation value is required to
compensate the ambient temperature at the reference junction, to
obtain a temperature value related to 0 C.
Temperature sensor consisting of two different metals (e.g. iron,
constantan); supplies a voltage dependent on the temperature
difference between the measuring junction and the reference
junction.
Controller with two switching contacts as output (heat, off, cool,
or right, off, left = three switching statuses).
Method of connecting resistance thermometers to compensate
the influence the lead resistances.
Integral action time (describes the integral action of the
controller).
Temperature values above and below the required temperature
(setpoint). If these tolerances are violated, signals are generated
by the control variable so that corrective action can be taken.
Memory on the IP 244; can be written to and read from both by the
programmable controller and by the microprocessor on the
module.
Controller with one switching contact as its output (two switching
statuses).
Glossary
9–7