DESCRIPTION
The
HX11, HX12, HX13, and HX21 relative humidity and temperature transmitters
provide temperature compensated RH output and linearized RH and temperature
outputs. A thin film polymer capacitor senses relative humidity, and the
tempera-ture sensor is an integrated circuit temperature sensor. The sensors
are protect-ed by a stainless filter that is easily removable for cleaning.
A low compliance voltage (12 volts) allows the use of large impedances for
longer wire runs.
FEATURES
Duct and surface
mount design ideal for HVAC application
Available in 4 different
styles
316 Stainless steel
and ABS NEMA-4 enclosure protects surface mounted electronics
Compact design allows
easy mounting in tight locations
Two standard 4-20mA
or 1-5V outputs
2% RH, 0.6░C accuracy
AVAILABLE MODELS
The following models are available:
|
PART
#
|
DESCRIPTION |
|
HX11C
|
RH/Temperature
transmitter with 3 ft lead wires and current output |
|
HX11V
|
RH/Temperature
transmitter with 3 ft lead wires and voltage output |
|
HX12C
|
RH/Temperature
transmitter with Bendix 4-pin connector and current output |
|
HX12V
|
RH/Temperature
transmitter with Bendix 4-pin connector and voltage output |
|
HX13C
|
RH/Temperature
transmitter with 1/2" male NPT fitting and 3 ft leads and current
output |
|
HX13V
|
RH/Temperature
transmitter with 1/2" male NPT fitting and 3 ft leads and voltage
output |
|
HX21C
|
RH/Temperature
transmitter for surface mounting. Compression strain relief for wiring
and current output |
|
HX21V
|
RH/Temperature
transmitter for surface mounting. Compression strain relief for wiring
and voltage output |
UNPACKING
Remove the Packing List and verify that all equipment has
been received. If there are any questions about the shipment, use the phone
numbers listed on the back cover to contact the Customer Service Department
nearest at (714) 540-4914.
Upon receipt of shipment, inspect the container and equipment for any signs
of damage. Take particular note of any evidence of rough handling in transit.
Immediately report any damage to the shipping agent.
Note: The carrier will not honor any claims unless all shipping material
is saved for their examination. After examining and removing contents, save
packing material and carton in the event reshipment is necessary.
Verify that you receive
the following items in the shipping box:
|
QTY
|
DESCRIPTION |
|
1
|
HX
Series RH/Temperature Transmitter |
|
1
|
Operator's
Manual |
Note: A NIST
certificate is available on request.
THEORY
OF OPERATION
A 4-20mA loop is a series loop in which a transmitter will vary the current
flow depending on the input to the transmitter. In the HX11C, HX12C, HX13C
and HX21C, the amount of current allowed to flow will vary depending on
the relative humidity. Some of the advantages of a current output over a
voltage output is that is less susceptible to noise interference and it
allows the connection of more than one meter or recorder to the loop as
long as the maximum resistance is not exceeded.
The typical current loop will consist of a power supply, a transmitter and
a meter to measure the current flow. The loop resistance is the sum of the
impedance of the meter(s) and the lead wire. The maximum allowable loop
impedance for the HX11C, HX12C, HX13C, and HX21C is found by using the formula:
Rmax = (power supply voltage - 12 volts) / 0.02
amps
Example: When using a 24 VDC power supply:
|
Rmax
=
|
24
- 12 = 600
|
| |
0.02
|
If the meter or recorder being used accepts only voltage, then the current
can be converted to a voltage using a shunt resistor, and Ohm's law (voltage
= current x resistance). By installing a 250 ohm resistor across the input
terminals of the recorder, the input voltage would equal 1 - 5 volts.
|
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