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Users Manual & Installation Guide
PV- 5127: Power supply module with UPS
Page 12 of 31
System temperature
The PV-5127 has a temperature measuring circuit that can control an external fan and heater, and
prevent the CPU from starting if the temperature is too low or too high. It monitors the system
temperature as long as +5V STB is on.
As system temperature sensor, you can use the onboard sensor, or an external sensor of type
Infineon KTY 11-5 connected to J2 (labelled “Ext. sensor”). If you don’t want any temperature
control, you can also configure it to a simulated 10°C, which effectively disables the temperature
control.
The circuitry checks for four different temperature ranges: too cold, cool, warm, and too hot.
Range Thresholds
Too cold
Below (0°C, 3°C)
Cool
Between (0°C, 3°C) and (15°C, 18°C)
Warm
Between (15°C, 18°C) and (47°C, 55°C)
Too hot
Above (47°C, 55°C)
There is hysteresis when moving between the ranges. The notion (0°C, 3°C) denotes the lower and
upper hysteresis levels, so that the change from too cold to cool happens when the temperature rises
above 3°C, but to change from cool to too cold, the temperature must fall below 0°C. Similarly for
the threshold between cool and warm (at 15°C and 18°C), and between warm and too hot (at 47°C
and 55°C).
For testing purposes, the too cold and too hot ranges can be simulated. To simulate too cold, mount
a jumper on J2 instead of a sensor. To simulate too hot, leave both J2 and ST3 unconnected.
The temperature ranges are used for these functions:
Range
CPU start
allowed Heater Fan Critical alarm
Cold
LED
Hot
LED
Too cold
No On Off No Flashing Off
Cool
Yes Off Off No Off Off
Warm
Yes Off On No Off Off
Too hot
No Off On Yes Off Flashing