Siemens SINAMICS S120 Manual page 219

S3 braking resistor monitoring
Table 5- 45
Function
Braking resistor
monitoring
When monitoring is activated, the switch-on ratio (ratio between ON time and OFF time) set
for the braking resistor on potentiometer "PD" is evaluated electronically.
If the set switch-on ratio is exceeded, the "MUL - Overload message" LED will be activated
and at the same time the centralized fault indication will be triggered at terminal -X2:4/5,6.
The fault message can be used by a higher-level controller to ensure timely shutdown,
thereby preventing damage to the connected braking resistor.
Monitoring is carried out solely on the basis of the switch-on ratio that has been set on
potentiometer PD, which means that the actual temperature of the braking resistor is not
monitored.
PD, switch-on ratio of the braking resistor
The braking resistor's switch-on ratio (ratio between ON time and OFF time) is set via
potentiometer PD. The setting made is only evaluated when activated via the S3 switch.
The adjustable values for the switch-on ratio at potentiometer PD correspond to the graphic
below. A value of "40%" is used for the default factory setting.
Figure 5-37
Brake type
P
15
P
150
P
270
P
DB
Cabinet Modules
Manual, (GH5), 05/2010, A5E03263538A
Braking resistor monitoring S3
Meaning
0 (open) = Monitoring active
1 (closed) = Monitoring disabled
CAUTION
Setting of the switch-on ratio
Description
Power that is permissible for 15 s every 600 s
Power that is permissible for 150 s every 600 s
Power that is permissible for 270 s every 600 s
Continuous braking power
Cabinet Modules
5.7 Central Braking Modules
PD setting
14 % (min.)
23 %
12 %
40 % (max)
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