6
RS-485 SERIAL BUS
6.1
GENERAL DESCRIPTION AND FEATURES
The amplifier is equipped with a RS-485 interface allowing connection as a slave to an asynchronous,
half-duplex, multi-drop, four-wire bus. This gives full remote control and monitoring of the amplifier as
part of an integrated system.
The following section describes the main features, protocols and operation of the amplifier with the
multi-drop serial bus.
6.1.1 HPA
Type?
A data request command that prompts a response giving the amplifier type number and software
issue (see section 6.3.3).
6.1.2 Status?
A data request command that prompts a response of 9 data byes, within which the status flags are
contained (see section 6.3.3). The following list summarises the status flags available on the 9 data
bytes:
D1
Summary fault
Indicates that the amplifier has seen at least on of the fault conditions
described in this section. The amplifier operation and reset conditions will be
dependent upon the fault present.
Transmitting
Indicates that the amplifier is operating in the transmit state (full details of the
operating modes are given in section 4.3).
Standby
Indicates that the amplifier is operating in the standby state (full details of the
operating modes are given in section 4.3).
Warm-up
Indicates that the amplifier is operating in the warm-up state (full details of the
operating modes are given in section 4.3).
Off
Indicates that the amplifier is operating in the off state (full details of the
operating modes are given in section 4.3).
D2
Output to antenna
When using the redundant switch control feature, if set, indicates that the
amplifier is routed to the Antenna. If no set, indicates that the amplifier is
route to the Load. See section 6.1.3 for details on the operation of the
redundant switch control feature.
Power too high
Indicates that the high power alarm is set and that the RF output power is
above the alarm level. The amplifier will remain in the transmit state, but with
the RF inhibited. until either -
The RF output power falls below the alarm level (decrease the RF
input power or increase the internal digital attenuator, if fitted) and an
‘RF enable’ request is sent to clear the ‘RF inhibit’
or -
The high power alarm is disabled (see section 6.1.5).
High power alarm
Indicates that the high power alarm is enabled. See section 6.1.5 for details
enabled
on
enabling, disabling and operation of the power alarms.
D3
Power too low
Indicates that the low power alarm is set and that the RF output power level is
below the alarm level. The amplifier will remain in the transmit state, but the
fault flag will only clear once either -
The RF output power level exceeds the alarm level
or -
The low power alarm is disable (see section 6.1.5)
Low power alarm
Indicates that the low power alarm is enabled. See section 6.1.5 for details
enabled
on enabling, disabling and operation of the power alarms.
RF enabled
Indicates that the RF is enabled. The RF enabled/inhibited commands are
accepted in any of the operational modes. See section 6.1.7 for details on
enabling/disabling the RF inhibit feature.
Remote enabled
Indicates that the amplifier is in remote mode allowing control via the serial
communications interface. See section 6.1.12 for details on enabling and
disabling remote mode.
© e2v technologies (uk) limited 2010
DAS768892AA
Version
1,
page
23
