Temperature Step Controller Fb59 "Tcont_S - Siemens SIMATIC Manual

Temperature Step Controller FB59 "TCONT_S"

Process Value Format Conversion CRP_IN (PER_MODE)
The CRP_IN function converts the peripheral value PV_PER to a floating-point
format depending on the switch PER_MODE according to the following rules:
PER_MODE
0
1
2
Process Value Normalization PV_NORM (PF_FAC, PV_OFFS)
The PV_NORM function calculates the output of CRP_IN according to the following
rule:
"Output of PV_NORM" = "Output of CPR_IN" * PV_FAC + PV_OFFS
This can be used for the following purposes:
•
Process value correction with PV_FAC as the process value factor and
PV_OFFS as the process value offset.
•
Normalization of temperature to percentage
You want to enter the setpoint as a percentage and must now convert the
measured temperature value to a percentage.
•
Normalization of percentage to temperature
You want to enter the setpoint in the physical temperature unit and must now
convert the measured voltage/current value to a temperature.
Calculation of the parameters:
•
PV_FAC = range of PV_NORM/range of CRP_IN;
•
PV_OFFS = LL(PV_NORM) - PV_FAC * LL(CRP_IN);
where LL is the lower limit
With the default values (PV_FAC = 1.0 and PV_OFFS = 0.0), normalization is
disabled. The effective process value is output at the PV output.
4-2
Output of Analog Input Type
CRP_IN
PV_PER * 0.1 Thermoelements; PT100/NI100; standard
PV_PER * 0.01 PT100/NI100; climate
PV_PER * Voltage/current
100/27648
Unit
°C; °F
°C; °F
%
PID Temperature Control
A5E00125039-02