2 fault and error response – Comtech EF Data KST-2000A/B User Manual
Page 78
Ku-Band Satellite Transceiver
Revision 9
Operation
MN/KST2000AB.IOM
3–30
When the uplink AGC is enabled (
clude a decimal point. Attenuation is adjustable over a range of 0 to 20 dB in 1 dB steps.
When the uplink AGC is disabled (
not include the decimal point.
3.11.2
Fault and Error Response
Table 3-7 shows how the AGC system reacts to power outages, system faults and opera-
tion outside the specified limits.
Table 3-7. AGC Fault and Error Response
Problem
Response/Notes
If the transceiver prime power fails
The UCA value is effect prior to the failure is restored on power up.
If the input signal (70 or 140 MHz) is re-
moved or is set to
≤ –45dBm.
1. The internal Up Converter attenuator is set to its maximum value
(minimum gap).
2. The value of UCA is not affected.
3. The output power will slowly increase for several seconds until the
gain error reaches zero, when the input signal is reapplied.
If the user enters a value of UCA that is low
for a set input level.
1. The SSPA will be driven into saturation and the value of UCA will
automatically increase (Gain decreased) in steps of 1 dB until the
SSPA output power is below saturation.
2. The new (increased) value of UCA is displayed at the user’s inter-
face. Even if the input power is reduced, the new value of UCA will
remain fixed.
If the input power is increased, such that
the SSPA is driven into saturation.
1. The value of UCA is increased (Gain decreased) in steps of 1 dB
until the SSPA is below saturation.
2. The new value of UCA is displayed at the user’s interface. Even if
the input power is reduced, the new value of UCA will remain
fixed.
Loop fault occurs when the Gain Error is
nonzero for >5 out 255 iterations of the
processor control loop.
1. A top level AGS_Fault is reported.
2. Excessive cable loss between the converter unit and the SSPA
can cause this condition.
3. If the AGC is enabled and the RF is commanded Off
( INSUFFICIENT INPUT POWER fault is Under this condition, a top level AGS_fault is reported and the internal EXCESSIVE INPUT POWER fault is gen- Under this condition, a top level AGS_Fault is reported. If the combina-
generated when the IF input power transi-
tions from normal power to low power (< –
45 dBm).
up converter attenuator is set to its maximum value (minimum RF out-
put). The value of UCA is not affected. When the input signal increases
above –45 dBm, the output power will slowly increase for several sec-
onds until the gain error reaches zero.
erated when the IF input power transitions
from normal power to high power (> –25
dBm).
tion of the input power and the up converter attenuator is such that the
SSPA is driven into saturation, the value of the UCA will automatically
increase in steps of 1 dB until the SSPA output power is below satura-
tion. The new value of UCA is displayed at the user’s interface. Even if
the input power is reduced, the new values of UCA will remain fixed.
The LOOP, INSUFFICIENT INPUT POWER, and EXCESSIVE INPUT POWER faults
can be displayed by issuing the AGC current faults command (
lowed ranges of IF input power and UCA settings are limited by the SSPA saturation and
detector range to the shaded area defined in Figure 3-18.