Siemens SIMATIC S5 Manual page 325

Symbols and abbreviations for variables and values
BW
F
HCR
K
P
K
S
ST
H
ST
K
T
A
T
AK
T
AZ
T
g
T
N
T
NK
T
U
T
UH
T
UK
T
V
T
VK
T
Z
W
1
W
2
W
A
X
d
X
P
X
PK
Y
Y
H
Y
A
Y
AS
Z
A
ZONOB
ZONUN
IP244
C79000–Y8576–C858–02
Limit value, limits the influence to a secondary setpoint.
Evaluation factor, value for the influence of the master controller.
Heating-cooling ratio, parameter for balancing different heating
or cooling capacity with three-step controllers.
Proportional coefficient or gain factor ( = 100/ X
Transfer coefficient (control system)
Maximum slope when heating
Maximum slope when cooling
Sampling time
Sampling time when cooling
Approach time
Response time (control system)
Integral action time (describes integral action)
Integral action time for cooling
Delay time (replaces dead time)
Delay time when heating
Delay time when cooling
Derivative action time, describes derivative action (also T
Derivative action time for cooling
Filter time constant for damping the derivative influence
Operational setpoint
Lower setpoint
Approach setpoint
System deviation (system difference)
Proportional band ( = 1/ K
P
Proportional band for cooling
Manipulated variable
Manual manipulated variable
Response value
Approach manipulated variable
Approach zone
Zone upper limit, no control above it, manipulated variable at end
or start of area.
Zone lower limit, no control below it, manipulated variable at start
or end of area.
)
P
)
Glossary
)
D
9–9