Input Of Parameters For Heating Current Monitoring - Siemens SIMATIC S5 Manual

3.3.3 Input of Parameters for Heating Current Monitoring

– Heating current monitoring
The setpoint for current is entered in messages 6 to 11, bytes 0 and 1. Byte 2 is for the positive
tolerance and byte 3 for the negative tolerance. The tolerances must be entered relative to the
setpoint. If the setpoint for current is selected as zero, the corresponding current monitoring is
disabled, error messages are cleared and the actual value indication for current is set to 0.
The IP is to be informed about the current calibration value entered in bytes 4 and 5.
Formula to calculate the current calibration value I
I = nominal current [A]
cal
Example of how to determine the current calibration value:
The nominal current consumption of the monitored system part is 15 A
The current converter outputs a pulsating direct voltage of 21.2 mV at a 15 A
current calibration value I
cal
25.6 [mV]
I = 15[A]
cal
21.1 [mV]
The number to enter the calibration value for the current is then 182 (unit = 0.1 A)
The current monitoring remains active if a controller is switched off by a temperature setpoint equal
to zero or when the heating switch is OFF.
– Actual current value monitoring
The setpoint for the power supply voltage is entered in message 13, bytes 0 and 1. Byte 2 is for the
positive tolerance of the power supply voltage actual value and byte 3 for the negative tolerance.
The tolerances must be entered relative to the setpoint. If the setpoint is set to zero, the power
supply voltage is not monitored and the heating current is not weighted with the actual power supply
voltage value. In addition to this, the error messages are cleared and the power supply voltage
actual value indication is set to 0.
A voltage calibration value must be transferred to the IP with message 13, bytes 4 and 5. Here, the
power supply voltage value corresponding to a sinusoidal half-wave signal with a peak voltage of
10.24 V at the module input (see Fig. 3.3.4/1) must be entered.
Formula to calculate the voltage calibration value U
U = nominal voltage of the power supply [V]
cal
Example of how to determine the voltage caibration value U
The nominal voltage of the power supply is:
Peak value of the nominal voltage is:
The voltage converter is a 50:1 voltage divider:
this means for the IP 244 that:
The voltage calibration value is then:
10.24 [V]
U = 220 [V]
cal
The number to enter as the calibration value for the voltage is then 362 (unit = 1V).
IP244
C79000–B8576–C860–02
cal
25.6 mV
peak output voltage of current converter [mV]
is then:
= 18.2 A
voltage at the output of the voltage converter [V]
U
eff
U
peak
U
E
= 362 V
6.22 [V]
Special Functions for Plastic Machines
:
eff.
eff
:
cal
10.24 mV
:
cal
= 220 V
.
= 220 V 2 = 311 V
= 311 [V] / 50 = 6.22 V.
input current. The
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