4-4
Airnet® II 4-Channel Particle Sensors Operations Manual
Chapter 4
: 4-20 mA Signal Configuration / Operation
Configuring 4-20 mA Outputs
Configuration Commands
The following commands are available to use when setting 4-20 mA signal parameters.
?
Displays a command summary (a summary of the information in this table).
sta(tus)
If in PMS Operational mode, displays the current firmware version number, MAC
address, IP address, Multicast address, Net mask, gateway, and connection status. It
will also display current 4-20 mA parameters if that option was selected.
set sam(ple) x y
This function sets the minimum sample interval to
x
seconds and the maximum
sample interval (used when zero particles are detected) to
y
seconds.
This value is stored in permanent memory and is used by the instrument when it starts.
This value can be changed by means of the Ethernet interface (Facility Net). However,
when the Airnet II 4-Channel particle sensor is de-energized, the value set by the
Ethernet interface is replaced by the value in permanent memory. When the 4-20 mA
option is used, it always runs by the first sample interval.
set cum(ulative) n
This function selects between cumulative and differential data for the first four
configurable 4-20 mA outputs if that option is available.
If
n
equals 1, the data is cumulative and represents the number of particles detected
that are larger than the size specified for the channels.
If
n
equals 0, the data is differential and represents the number of particles detected
that are between the sizes specified for each output channel.
set eos n
If
n
is set to 1 then the data in each channel is updated only at the end of each sample
interval and is held constant for the duration of the subsequent sample interval. If
n
is
equal to 0, the 4-20 mA channels are updated approximately every 100 milliseconds.
set raw n
If
n
is 1, the data in each channel is simply the number of particles detected. If
n
is 0,
the data is normalized by dividing the counts by the volume sampled. The output units
are counts per cubic foot.
set sca(le) n,n,n,n
This value defines the scaling of the first four 4-20 mA channels. This value corresponds
to 20 mA at the output. The lower end of the range is always defined so that 4 mA
corresponds to zero. The units of this value are defined by the settings entered by the
cum
and the
raw
commands. The first
n
applies to channel 1. The second
n
applies to
channel 2, etc.
write
Saves the most recent changes.
You must send this command
after completing the
instrument setup, or your parameters will be lost when the sensor is de-energized.
