PPD Maintenance Manual
T1DA0502-002, Rev A
Page 7
In the older Range type 0 Flare systems, the range programmed into the sensors would not be
translated by offset, (for the example in section 2.1.1, the range downloaded to the sensors for
100 PPDs starting at ID 1001 would be 1001 – 1600, to handle the PPD IDs 1001-1100 and the
low battery IDs 1501-1600).
2.1.3 Range Type 1
In the Range type 1 Flare and Flash systems, the range programmed into the sensors is translated
by offset, (for the example in section 2.1.1, the range downloaded to the sensors would be 1468-
2068). However, the PPD offset in range type 1 does not follow the rules of range type 0 and can
be any value - ideally zero. Therefore we can have the much simpler case:
For a user-programmed ID of 1001 in 12 bit mode (with PPD offset = 0 & LB offset = 500)
PPD transmit ID = 1001 + 0 = 1001 = PPD ID
PPD transmit ID for LB = 1001 + 0 + 500 = 1501
The range that is downloaded to the sensors for 100 PPDs starting at 1001 would be 1001-1600.
No offset is added to the PPD ID or range, and no offset is subtracted by the system.
2.1.4 Low Battery Offset
In 12 bit mode, the system will examine the incoming PPD transmit ID value, subtract the PPD
offset, and compare the result to the minimum and maximum ID values in its ini file. In this way,
the system will determine if the received alarm is a low battery alarm. If it is a low battery alarm,
the system will subtract the low battery offset and display the correct PPD ID.
Newer PPD firmware (program code version 3.00 and above) supports 14 bits of modulation.
This can be used with Range type 1 systems. In 14 bit mode the 2 additional bits are available to
provide alarm type information, push-button, low-battery, pull-pin, and man-down. In this case,
no low battery offset is used.
Systems with new hardware (Range Type 1), with 14 bit PPD IDs have no offsets, or extended
range for low battery, and are therefore, simpler. Especially when adjacent sites require non-
overlapping PPD ranges.
Existing sites must keep offsets and ranges as originally established. Note your existing ini file
settings and record them in site specific documentation.
The following table shows the offset and range guidelines for legacy installations.
Parameter
Flash 12 bit
Flare Range
Type 0
Flare Range
Type 1, 12 bit
Flare Range Type
1, & Flash 14 bit
PPD Offset
467 (could be 0)
467 or –3300
0
0
Low Battery
Offset
300, 500 or 1000
300, 500 or 1000 300, 500 or 1000
N/A