Signal voltage levels:
Minimum value Nominal value
Maximum value
RS-232 communications
RS-232 input threshold low
0.8 V
1.5 V
–
RS-232 input threshold high
–
2.0 V
2.4 V
RS-232 input absolute maximum
–15 V
–
+15 V
RS-232 input resistance
12 KΩ
–
–
RS-232 output voltage low
–
–
0.4 V
RS-232 output voltage high (into 3 KΩ)
4.4 V
–
–
RS-485 communications
RS-485 input threshold voltage
–0.2 V
–
+0.2 V
RS-485 output (unloaded)
–
–
5V
RS-485 output (load 50 Ω)
2 V
–
–
Maximum voltage at any terminal
–7 V
–
+7 V
3.4 Environmental specifications
Temperature ranges
Operating:
–25 to +60 °C
Extended operating:
–40 to +70 °C (only guaranteed if sensor has been
tested and verified by Campbell Scientific
to operate over this range)
Storage:
–40 to +85 °C
Sensor heater thresholds
Dew heater turn on:
<35°C
Dew heater turn off:
>40°C
Hood heater turn on:
<5°C
Hood heater turn off:
>15°C
Ingress protection:
IP66
CS140 Background Luminance Sensor
4
