LED Indicators:
2-5
LED Indicators
Overload
Flashing of the OVERLOAD LED indicates a steady input
overload. When the input voltage drops below the overload
level, the OVERLOAD LED will remain illuminated
(latched on) until reset.
Signal Present
The SIGNAL LED is illuminated when the output signal
exceeds 45 mV. The brightness will increase with the signal
level in a manner approximately proportional to the log of
the voltage.
External Power
The presence of an external voltage (10.5 - 30 Vdc) is
indicated by the illuminated EXTERNAL POWER LED
Battery Voltage
The internal battery voltage is indicated by the illumination
of one of the BATTERY VOLTAGE LEDs as indicated in
Table 2-2.
Battery Compartment
The Model 2221 is powered by six AA batteries. The battery
compartment is accessed from the bottom by removing the
LED
Battery Voltage
(Volts)
6
5.5 to 6.5
7
6.5 to 7.5
8
7.5 to 8.5
9
8.5 to 11.3