H7625B; H7635B,C; H7655B
Duct-Mount and Outdoor-Mount
Humidity/Temperature Sensors
INSTALLATION INSTRUCTIONS
Mounting
APPLICATION
The method of mounting depends on the particular
sensor application. The following procedures include
outdoor and duct applications. Also refer to the
instructions for the electronic control.
The H7625B, H7635B, H7655B Duct-Mount and H7635C
Outdoor-Mount Humidity/Temperature Sensors are
universal Relative Humidity transmitters that can be
powered with either a +18 to 36 Vdc or 24 Vac supply.
The sensors use a half-wave bridge rectifier to convert
AC power to a usable DC voltage. The device also
includes a 20K ohm temperature sensor for optional use.
Duct Mounting
The H7625B, H7635B and H7655B can be mounted in a
duct to sense humidity and temperature.
The humidity sensors are designed with a field-
IMPORTANT
selectable 4 to 20 mA, 0 to 5 Vdc, or 0 to 10 Vdc output
signal equivalent to 0 to 100% RH. All units are shipped
from the factory with a default setting to accept AC power
with three-wire, 0 to 10 Vdc loop-powered output.
Select a location to expose sensor to average
duct humidity and temperature. Avoid locations
where stratification can cause sensing errors.
NOTES:
—
H7635C is weatherproof for outdoor use.
Knockouts allow 1/2 in. conduit connection.
To avoid damaging board during installation,
the cover can be detached completely:
1.Carefully remove wire plug from board.
2.Set the cover aside.
INSTALLATION
—
When Installing this Product...
1. Read these instructions carefully. Failure to follow
them could damage the product or cause a
hazardous condition.
2. Check ratings given in instructions and on the
product to ensure the product is suitable for your
application.
3. Installer must be a trained, experienced service
technician.
4. After installation is complete, check out product
operation as provided in these instructions.
1. Cut a hole in the duct just large enough to accept
the sensing element.
2. Open case by rotating the cover counterclockwise.
3. Mount standard 1/2 in. conduit to the case.
4. Use case to mark mounting screw pilot hole
locations.
5. Drill the pilot holes and fasten the sensor to the
duct.
6. Wire the sensor. See Wiring section.
NOTE: The two free wires are thermistor wiring
connections. When connecting these, use
two wire nuts.
CAUTION
Electrical Shock or Equipment Damage
Hazard.
7. Reattach the wire plug and cover being careful not
Can shock individuals or short equipment
circuitry.
to pinch wires between the cover and case.
Disconnect power supply before installation.
CAUTION
Equipment Damage Hazard.
Improper wiring can damage the sensor
beyond repair.
Follow the wiring instructions carefully.
63-2579—3
H7625B; H7635B,C; H7655B DUCT-MOUNT AND OUTDOOR-MOUNT HUMIDITY/TEMPERATURE SENSORS
WIRING
For voltage output, shielded cable (16-22 AWG) should
be used.
mA OUTPUT
TRANSDUCER
ONLY
18 TO 36 Vdc
POWER SUPPLY
For current output, either shielded cable or twisted pair
(16-22 AWG) can be used.
Vin
Io
+
–
NOTE: When using shielded cable, ground the shield
only at the controller end (see Fig. 2). Grounding
both ends can cause a ground loop.
CONTROLLER, METER
OR RECORDER
INPUT SIGNAL
+
The 20K ohm NTC temperature output is accessed
through the separate blue and green wires (located inside
the enclosure).
COMMON
–
GROUND
M22528
Fig. 2. Typical wiring diagram for transducer with two-
wire mA output and external DC power supply.
OUTDOOR
AIR
SENSOR
HEAT
RELAY 2
T7770 REMOTE SENSOR
DISCHARGE
AIR
SENSOR
9
8
7
6
5
4
3
2
1
COMPRESSOR
CONTACTOR 4
COMPRESSOR
CONTACTOR 2
T7350
SUBBASE
T5
T6
T7
T4
T3
OS
M
OS
M
AS
X
AS
W3/Y4 Y3
W2
Y1
Y2
G
5
HS
HC
HP
RH RC AUX W1
COMPRESSOR
CONTACTOR 3
FAN
RELAY
3
HEAT
RELAY 1
MOTION
SENSOR
Vo Gnd Vin
(0-10 Vdc) (Vac)
COMPRESSOR
CONTACTOR 1
HUMIDITY SENSOR
4
L2
L1
ECONOMIZER
1
2
(HOT)
1
2
3
4
5
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.
ENSURE TRANSFORMER IS SIZED TO HANDLE THE LOAD.
HEAT/COOL SYSTEMS WITH ONE TRANSFORMER REQUIRE THE FACTORY-INSTALLED JUMPER.
USE ECONOMIZER INSTRUCTIONS FOR INSTALLATION DIRECTIONS.
HC AND HP PROVIDE 24 VAC TO THE HUMIDITY SENSOR.
M22529
Fig. 3. Humidity sensor (0-10 Vdc output) wiring with T7350
(use with RH/Temperature combination T7350 units only).
3
63-2579—3
H7625B; H7635B,C; H7655B DUCT-MOUNT AND OUTDOOR-MOUNT HUMIDITY/TEMPERATURE SENSORS
H76XX
P7640
PWR
P7640
PWR
Vin (Vac)
Gnd
+
–
O
+
–
+
–
O
+
–
O
2
COM
OUT
COM
OUT
Vo (0-10 Vdc)
1
2
3
4
5
6
7
8
9
10
AI
11
12 13
1
AN
O
E
GND
AI
1
AI
2
AI
GND
AI
3
AI
4
AI
GND
AI
5
AI
6
AI
7
AI
8
AI
GND
W7760A
GND
AO
1
24
24
24
24
24
24
24 OUT 21 G
OUT OUT OUT OUT OUT OUT OUT OUT DI
1
DI
2
DI
3
DI GND GND
4
VAC VAC VAC VAC VAC VAC VAC COM VDC
COM COM OUT
1
2
3
4
5
6
7
8
17 18 19 20 21 22 23 24 25 26 27 28 29
31 32 33 34 35 36 37 38 39 40
L1
(HOT)
1
L2
1
2
POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED.
TEMPERATURE SIGNAL CONNECTIONS ARE NOT POLARITY SENSITIVE.
M18302B
Fig. 4. Typical wiring diagram for 5-wire temperature/humidity sensor with Vdc output
(used with the XL15A controller).
63-2579—3
4
H7625B; H7635B,C; H7655B DUCT-MOUNT AND OUTDOOR-MOUNT HUMIDITY/TEMPERATURE SENSORS
CHECKOUT
Converting Output Signal to Percent RH
4 to 20mA Signal
⟨signal [in mA] – 4⟩
------------------------------------------------- = p e r c e n t R H
0.16
CAUTION
Equipment Damage Hazard.
Can short electric circuitry.
•
•
Never connect 120 Vac to the transducer.
Connect only DC voltage to a transducer
intended for DC supply.
Example: 12 mA output signal
(12 - 4)/ 0.16 = 50% RH
NOTE: Use laboratory quality meters and gauges for
applications requiring a high degree of accuracy.
0 to 10 Vdc Signal
1. Verify the transducer is mounted in the correct posi-
tion.
2. Verify appropriate input signal and voltage supply.
3. Verify appropriate configuration range.
Example: 8 VDC transmitter signal output
8 Vdc/0.10 = 80% RH
Table 2. Troubleshooting.
Items to Check
Problem
No reading
•
•
•
Verify correct supply voltage at the power terminal blocks.
Verify correct wiring configuration and DIP switch settings.
Verify that terminal screws are connected tightly with all wires firmly in place.
Erratic readings
•
•
•
Verify all wires are terminated properly.
Ensure that there is no condensation on the board.
Verify clean input power. In areas of high RF interference or noise, shielded cable can be
necessary to stabilize signal.
5
63-2579—3
H7625B; H7635B,C; H7655B DUCT-MOUNT AND OUTDOOR-MOUNT HUMIDITY/TEMPERATURE SENSORS
APPENDIX
RH Test and Configuration DIP Switch Settings (Table 3)
IMPORTANT
0% RH Output (for Testing Only)
Transmitter always outputs a signal of 4 mA or 0 Vdc. The
sensor does not affect the transmitter output.
•
Only adjust these switches for troubleshooting or
recalibrating the sensor. (Adjustment is not
normally necessary.)
•
For normal operation, always keep DIP switch 3
in the ON position. When DIP switch 3 is off, the
RH transmitter cannot read the sensor. This
inability-to-read forces the output to never
change.
50% RH Output (for Testing Only)
Transmitter always outputs a signal of 12 mA, 2.5 VDC, or
5 VDC. The sensor does not affect transmitter output.
100% RH Output
Table 3. Test/Calibration Settings (Six-Switch Block).
Transmitter always outputs a signal of 20 mA, 5 VDC, or
10 VDC. The sensor does not affect the transmitter
output. Sensor doesn’t affect the transmitter output.
Setting
Normal Operation (Default)
0% RH Output
6
5
4
—
—
3
2
1
—
—
—
—
—
—
On —
On —
—
—
—
—
—
Normal Operating Condition
DIP switch 3 must be set in the On position for normal
operation. All other DIP switches must be set Off.
50% RH Output
—
—
—
—
—
On —
100% RH Output
—
—
—
—
On —
Increment RH Output
Decrement RH Output
Reset to Original Calibration
—
—
—
—
—
—
On —
—
On
On On
63-2579—3
6
H7625B; H7635B,C; H7655B DUCT-MOUNT AND OUTDOOR-MOUNT HUMIDITY/TEMPERATURE SENSORS
CALIBRATION
All transducers are factory calibrated to meet/exceed published
specifications. Field adjustment should not be necessary.
Using Calibration Trim Potentiometers
IMPORTANT
IMPORTANT
•
Due to sensitive nature of humidity calibration,
adjusting trimmer potentiometers is not highly
recommended.
•
•
•
•
Do not verify comparative RH with a sling
psychrometer. Too many variables exist which
induce errors into this process.
Recalibration must be done in a controlled
environment. Relative humidity must be held
stable while making any adjustment.
Verify the device output directly with calibrated
instrumentation and verify RH with calibrated
instrumentation. Never use a controller output.
With correct power applied, and only a meter
connected to the transducer output, ensure that
the output is proportional to the true RH.
•
Calibrate only in a stable humidity/temperature
chamber of laboratory grade.
Single Point Calibration
IMPORTANT
Use only one of the following two options.
OPTION 1
1. Select a controlled humidity environment between
10 and 40 percent RH. Be sure humidity is stable.
2. Adjust zero trimmer (z).
Using Increment/Decrement Switches
OPTION 2
Increment RH Output
1. Select a controlled humidity environment between
40 and 70 percent RH. Be sure humidity is stable.
2. Adjust span trimmer (s).
This DIP switch allows you to calibrate the sensor through
the software. The switch must be toggled from the Off to
the On position and then returned to the Off position for
an increase of 0.5% RH. This means that if your humidity
has drifted 1% lower over a certain time period, you can
toggle the Increment RH Output switch (2 times) in order
to slide the whole curve upward 1%.
Two Point Calibration
1. Select a controlled humidity environment between
10 and 40 percent RH. Be sure humidity is stable.
2. Adjust zero trimmer (z).
3. Select a controlled humidity environment between
70 and 75 percent RH. Be sure humidity is stable.
4. Adjust span trimmer (s).
Decrement RH Output
This DIP switch allows calibration in the same way as the
Increment RH. The difference is that each toggle results
in a decrease of 0.5% RH.
7
63-2579—3
®
LonSpec™ is a trademark of Echelon Corporation.
Automation and Control Solutions
Honeywell International Inc.
1985 Douglas Drive North
Golden Valley, MN 55422
customer.honeywell.com
Honeywell Limited-Honeywell Limitée
35 Dynamic Drive
Scarborough, Ontario M1V 4Z9
® U.S. Registered Trademark
© 2005 Honeywell International Inc.
63-2579—3 B.B. Rev. 01-05
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