Lighthouse solair 3100, Operating Manual

Page: 175 / 188

MODBUS Register v1.48
248083389-1 Rev B-17
Threshold Setup Registers
Threshold data is stored in the input registers in the 45xxx series which
are read/write. All threshold data items are 4 bytes long and are stored
across 2 registers. Byte and word ordering is big-endian. Thus, data
items are formed by placing the high bytes in front of the low bytes.
For example:
<High Bytes><Low Bytes> = <4 Byte Data Item>
For particle channels, the threshold value is a 32-bit unsigned integer.
If the data value exceeds the threshold value and the alarm is enabled
for that channel, the threshold flag in the Data Status register (30007-
30008, bit 4) is set.
Note:
The table below
shows the registers for an
8 channel particle counter.
Counters with fewer
channels do not use the
extra registers. The
smallest particle channel
starts at the xxx09 position.
The threshold registers (45xxx series) run in parallel with the data
registers (30xxx series). For example, data register 30010’s
corresponding threshold register would be 45010. Data register 30016’s
threshold register would be 45016.
Table B-16 Alarm Threshold Registers
Register Data Type Description
45009 unsigned int Threshold for Particle Channel 1 [high]
(smallest particle size starts here)
45010 unsigned int Threshold for Particle Channel 1 [low]
45011 unsigned int Threshold for Particle Channel 2 [high]
45012 unsigned int Threshold for Particle Channel 2 [low]
45013 unsigned int Threshold for Particle Channel 3 [high]
45014 unsigned int Threshold for Particle Channel 3 [low]
45015 unsigned int Threshold for Particle Channel 4 [high]
45016 unsigned int Threshold for Particle Channel 4 [low]
45017 unsigned int Threshold for Particle Channel 5 [high]
45018 unsigned int Threshold for Particle Channel 5 [low]
45019 unsigned int Threshold for Particle Channel 6 [high]
45020 unsigned int Threshold for Particle Channel 6 [low]
45021 unsigned int Threshold for Particle Channel 7 [high]
45022 unsigned int Threshold for Particle Channel 7 [low]