Technical data

Table Of Contents
Glossary
System Software for S7-300/400 System and Standard Functions - Volume 2/2
Glossary-12
A5E00739858-01
Ratio Control
Single loop ratio controller
A single loop ratio controller is used when the ratio of two process variables is
more important than the absolute values of the variables.
SP
-
LMN
Quotient
Ratio
PV1
PV2
Controller Process
Multi-loop ratio controller
In a multi-loop ratio controller, the ratio of the two process variables PV1 and
PV2 must be kept constant. To do this, the setpoint of the 2nd control loop is
calculated from the process variable of the 1st control loop. Even if the process
variable PV1 changes dynamically, the ratio is maintained.
SP
-
LMN1
Controller 1
Process 1
-
Factor
PV2
PV1
Process 2
Controller 2
LMN2
Remote Device
Remote devices are devices, for example, printers or computers that are
obtainable on a network. In contrast to local devices, they must be assigned a
network address when they are installed.
Restart
When a CPU starts up (for example, when the mode selector is moved from STOP
to RUN or when the power is turned on), before cyclic program processing starts
(OB1), either the organization block OB100 (restart) or the organization block
OB101 (restart; only in the S7-400) or the organization block OB 102 (complete
restart) (complete restart) is processed first. In a restart the process-image input
table is read in and the STEP 7 user program processing is restarted at the point
where it was interrupted by the last stop (STOP, power off).
Result of Logic Operation (RLO)
The result of logic operation (RLO) is the current signal state in the processor
which is used for further binary signal processing. The signal state of the last RLO
decides whether or not certain operations are executed.