User's Manual

044-05156 Rev C 27
MCR21919-1-2 Configuration Switch
4.6.1.1.3 APC LED
The LED indicator located on the top right-hand corner of the subrack serves several functions. Under normal
conditions, the indicator is off. Anytime the APC function is engaged, either from an overdrive or voltage derating
situation, the indicator blinks. When the overdrive or voltage derating condition is removed and all the gain is
recovered, the indicator ceases to blink and remains off. During maintenance functions such as downloading
firmware and detector calibration, the indicator blinks to signify the beginning and end of those functions.
APC LED Sequence and Blink Rate
Operation Sequence Blink Rate
APC due to an overdrive On/Off 1 Hz
APC due to an over voltage On/Off/Off/On 1 Hz
APC due to an under voltage On/Off/Off/On 1 Hz
System firmware upgrade On/Off 0.1 Hz
Detector calibration On/Off 1 Hz
4.6.1.1.4 Gain Adjust
This potentiometer allows the subrack gain to be attenuated 0 to 10 dB in Normal operating mode, or 0 to 3 dB in
Constant Gain operation mode. Refer to Gain Modes later in this section.