The status of each amp is determined by measuring the current drawn from each amp and comparing the
measured value to a previously set nominal value. If the measured value de/- 15% from the nominal
(expected) value then the amp’s status will be “Alarmed”. When an amp’s status is alarmed its respective alarm
indicator will illuminate red. If the backup amp (AMP3) is not alarmed then the unit will switch it into the
signal path of the faulted amp with the highest priority. There are two possible priority settings, Priority 1 and
Priority 2. If Priority 1 is selected and both AMP1 and AMP2 are alarmed then AMP1 will be backed up.
If Priority 2 is selected and both AMP1 and AMP2 are alarmed then AMP2 will be backed up.
1.3.5 Power Supply Alarm
The 2282-122-21 redundant power supplies include DC to DC converter modules. The outputs of each DC to
DC converter are monitored. If any DC to DC converter fails the front panel LED above the power LEDs will
illuminate and the rear panel contact closure will activate.
1.4 M&C Interface
1.4.1 Remote Serial Interface
Protocol: RS232C, 9600 baud rate, no parity, 8 data bits, 1 start bit, and 1 stop bit.
(RS232C, RS422, or RS485 - option Q)
Connectors: Rear panel, DB9 female
1.4.2 Commands Table 1.2 lists the commands for the 2282-122-21 and briefly describes them.
After a command is sent the 2282-122-21 sends a return “>” indicating the command has been
received and executed.
General Command Format - The general command format is {aaCND...}, where:
{ = start byte
aa = address of unit (only used if in RS485 mode)
C = 1 character, either C (command) or S (status)
N = 1 character command or status request
D = 1 character or more of data (depends on command)
} = stop byte
2282-122-21 Manual, Rev. A
Page 8
07/01/20
TABLE 1.2 JJ10
1.2
J10 Pinouts (RS-232C/422/485*)
Pin
Function
1
Rx-
2
Rx+ (RS-232C)
3
Tx+ (RS-232C)
4
Tx-
5
GND
6
Alarm Relay: Common
7
Alarm Relay: Normally Open
8
Not Used
9
Alarm Relay: Normally Closed
