P. G.
TM0047
2-3
2.2 FAULT REPORTING
2.2.1 General
- The amplifier incorporates a number of circuits to detect deviations in
important performance parameters. The unit reports alarm conditions to a remote
Monitor unit such as the Model PS212.
The various functions are described in this section and may also be referenced in
Section 4 where the programming of amplifier options is discussed.
2.2.2 Report Types
- The unit generates two types of reports depending on the status
of the amplifier as determined by the built in monitor circuits. Each type consists of a
numeric code sent as low frequency tones along the coaxial cable for decoding at the
monitor unit.
Under normal operation the unit will transmit an "OK" code at intervals of approximately
80 minutes. This enables the system monitoring unit to keep track that the whole
system is connected and operational. In this mode a local green NORMAL LED lamp is
illuminated on the side of the amplifier.
In the event that a fault is detected in the amplifier, as described later, a "FAULT" code
is transmitted on the cable at intervals of approximately 80 seconds. In this mode a
local red FAULT LED is illuminated on the amplifier. Four LEDs on the side of the unit
indicate which specific local condition is causing the overall FAULT condition as
described in the next section.
In each case the code transmitted identifies the transmitting amplifier by the FAULT
CODE programmed in that particular amplifier as described later in Section 4.6. Before
shipment P.G. programs each amplifier with an arbitrary code from 1 to 199 which is
also shown by a label on the outside of the unit.
NOTE: -
Older models of P.G. bidirectional amplifiers such as the A181 or A188
transmitted only fault codes, but are compatible with the fault codes transmitted
by the A300. When used with a PS212 Monitor, the A181 or A188 codes
should be entered in the ID list as "FAULT ONLY" (TFO) type units. If the A300
is used with a PS200 PS/Monitor the OK code transmission (STATUS option)
should be disabled (section 4.4) as it will cause the PS200 to display a FAULT
alarm. Fault codes above 199 should not be set on any amplifiers since they
may be incorrectly interpreted by the newer PS212.
2.2.3 Fault
Conditions
- The A300 circuitry monitors four separate parameters in
the unit. These are (a) the bias currents drawn by devices in both the amplifiers and (b)
the presence of downlink RF output power in each band. Each function can be disabled
as described in Section 4, if the unit is being used in a restricted operational mode.
