Siemens SIMATIC S5 Manual page 322

Glossary
P
Parallel structure
Parameter
Peripheral (I/O) area
Percentage output
PESP
PLC
Process identification
Pt 100
Pulse duration modulation
RAM
Ramp slope
Reference junction
temperature
Reference potential
Response value Y
A
Rugged controller
Sampling controller
Sampling time T
A
Sampling time overflow
9–6
Proportional action of the controller.
Special type of controller structure (here: mathematical
technique); P, I and D sections act in parallel and are then added.
Variables used to adapt the controller structure and the controller
action to the process.
Address area for peripheral modules in the programmable
controller.
The output of the calculated manipulated variable (output signal
of the controller) as a percentage of the sampling time referring
to the approach time (cf. "Pulse Duration Modulation").
Group address signal on the S5 bus to address peripheral
modules.
Programmable controller
Acquisition of characteristic values of a particular system
(characterics of the control system) to optimize the tuning of the
controller action.
Platinum resistance thermometer (100 Ohms at 0 C according to
DIN 43760).
See "Percentage Output".
Random access memory (working memory); can be read to and
from.
Here, preset rate of temperature rise per time unit.
Reference temperature for the thermocouple voltage
(see "Thermocouple").
Central grounding point of the controller.
If the manipulated variable is close to 0 or 100%, the short ON and
OFF intervals can be suppressed by specifying a parameter (e.g.
an ON time for a fan of 100 ms is completely pointless). See
Programming Instructions for the IP 244, "messages 0 ... 12".
The rugged controller is a PID controller with supplementary
characteristics: it has an oscillation detector and a so-called
predictor, i.e. the actual value to be expected is calculated in
advance, and the controller reacts accordingly "foresightedly".
The controller parameters of the rugged controller depend on the
operating point and the current system deviation.
A controller which processes a new actual value at regular
intervals and calculates a new manipulated variable.
Period between two processing cycles of the PID calculation
program for one control channel. These periods are constant and
selectable within limits.
The sampling time calculated for the controller can no longer be
maintained owing to excessive data exchange.
IP244
C79000–Y8576–C858–02