Siemens SIMATIC Rack PC 840 - Temperature Monitoring;Indication

Hardware Information
7-6
SIMATIC Rack PC 840 Manual
A5E00104826-03
7.4.3 Temperature Monitoring/Indication
Temperature Monitoring
The temperature is measured by means of three temperature sensors. One sensor
monitors the processor temperature, the second the temperature in the area near
the processor module, and the third the temperature near the drives.
Flashing of the Temp LED indicates that the device is being operated in the limit
range.
If the temperature exceeds one of the three temperature values of the set
thresholds, a temperature error is registered with the following effects:
Reaction Option
Temp LED turns to red –
Device and CPU fans go to maximum rpms. –
SOM application is displayed –
Temperature errors do not occur during the normal approved use of the device. If a
temperature error occurs, check the following possible causes:
 Are the ventilation slots blocked?
 Is the filter heavily soiled?
 Is the fan working?
 Is the ambient temperature higher than the allowed value?
 Has the total capacity for the power supply been exceeded?
The temperature error remains saved until the temperatures have fallen below the
thresholds and are reset by one of the following measures:
 Acknowledge the error message via the SOM program
 Restarting the device.