Customer Questions and Solutions:
Question:
"Dear Met One Instruments, Inc.
I
have a client with a strange request: they would like to start and stop
sampling with an E-Sampler, E BAM, or BAM 1020 according to one
programmable wind direction, or within a certain angle. For instance
within 25 and 75 degrees, and with wind velocity above a programmable
speed only.
I'm
sure it is not possible with the standard software, but before saying
to the client that it is not possible I would like to ask your opinion.
This
client would like to find a way to identify and quantify the source of
pollution, for instance to sample only when the sampler is downwind to a
coal plant, cement mill, chemical plant, refinery, etc… to avoid
dilution of the sample."
Solution:
AutoMet 466A provides “sector control” for air samplers, as
well as various sensor alarm functions.
The AutoMet 466A has two alarm relays that can be used to directly
control an air sampler device. The two
alarm relays can be connected in either a logical AND or a logical OR circuit
to control the air sampler. One relay
can be alarming on a user selected multiple degree wide sector of wind
direction based on a user selected wind direction reference point in degrees. The other relay can be connected to a second
defined wind direction sector, or to the wind speed sensor. If used with wind speed, the wind speed range
alarm value can be also be user selected.
These alarm values also have user settable hysteresis to prevent
multiple alarms near the edge of the sector or near the wind speed set
point.
Any MOI wind sensor set can be used with the AutoMet 466A
for sector control. A single wind
direction or wind speed sensor can be used if only one alarm function is
required. If using a wind speed sensor only,
the dual alarms in the AutoMet 466A can be used as a wind speed alarm for high
wind speed alarm and high high wind speed alarm. This alarm function can also be used with
any other sensors connected to the AutoMet 466A, such as temperature alarms, humidity
alarms, or solar radiation level alarms.
When high current or line voltage level control or alarm
function is required, MOI can provide an external solid state interposer relay
capable of 250 VAC at 40 amps, as an accessory to the AutoMet 466A.
- Dennis Recla, Sr. Systems Engineer. Met One Instruments, Inc.
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