ANNEX A - MODBUS OVERVIEW
56
The cluster state (CS) reports the current status as follows:
0 -
Inactive
1 -
Active
3 -
Pre-alarm
5 -
Alarm
The field of view is considered to be a 256 x 256 square space with the origin in the top right hand
corner as you look out from the detector. The position of the centre of the alarm is reported by X,Y
coordinate values. The site of the alarm SX,SY is reported using the same coordinates to define a
box around the outside of the detected signal.
The base address for the register block is set in the PC configuration tool. The default is 00.
A1.4.2
THE FV300 COMMAND REGISTER
The command register allows the PLC to activate functions within the detector.
Command Codes
1
=
Initiate alarm test
2
=
Initiate manual OPM test
3
=
Reset latched alarm or faults
4
=
Mask OFF
5
=
Mask ON (inside mask area)
6
=
Mask ON (outside mask area)
Note:
Mask ON
/
OFF setting is maintained following a power cycle. The mask area is
defined using the PC configuration tool
A1.4.3
THE FV300 OVERALL STATUS REGISTER
The status register is a collection of flags that report the current state of the detector.
The Watchdog Heartbeat toggles from 0 to 1 or from 1 to 0 every 16 seconds.
MSB
LSB
Co
mman
d
Re
quest Bi
t
Command Code
MSB
LSB
Re
ser
v
e
d
Re
ser
v
e
d
Alar
m
Pre-Alar
m
Re
ser
v
e
d
Hardw
a
re
Fa
u
lt
W
indo
w
Obscured
W
indo
w
Di
rt
y
Re
ser
v
e
d
Re
ser
v
e
d
Alar
m T
e
s
t
Activ
e
OPM
T
e
st
Activ
e
Mask
Enab
led
Re
ser
v
e
d
Co
mman
d
Do
ne
W
atch
dog
He
ar
tb
eat
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