User Manual

PLUS System Manual Reader Data Interface 65
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The bit definitions in the alarm status and alarm enable words are as follows:
Bit Position
Alarm Source
Meaning
0
PLL Lock Lost
The Reader lost synchronization with the SDP. The Reader will
need to be recalibrated.
1
Reboot
The Reader has rebooted. When a PLUS system is initially
powered on, all readers will report this alarm and the alarm should
be cleared. After initial power up, this alarm indicates a loss of
power or other Reader problem. The Reader will need to be
recalibrated.
2
Sync Marker Error
This alarm indicates a problem with the sync marker from the SDP.
3-31
Reserved
Figure 3-5: Alarm Status and Alarm Enable Word Bit Position Definition
The following example shows the recommended processing flow to handle alarms. In this example, a
Reader is reporting a ―PLL Lock Lost‖ alarm.
10) TOA packet is received with alarm bit set. All subsequent TOA packets from this
Reader will continue to have the alarm bit set until the alarm is cleared.
11) Reader alarm status is queried using the following command:
SENDALARMSTATUS
12) Reader responds with 32-bit hexadecimal alarm status indicating that the ―PLL
Lock Lost‖ alarm is present:
0x00000001
13) Reader is commanded to clear the alarm condition:
CLEARALARM 0x00000001
If a Reader is being used to detect Tag presence only and not connected to a SDP, the ―PLL Lock Lost‖
alarm and the ―Sync Marker Error‖ alarm may be ignored:
SETALARMENABLE 0xFFFFFFFA