Honeywell H7625A Humidity Temperature Sensors Instruction Manual
- June 17, 2024
- Honeywell
Table of Contents
Honeywell H7625A Humidity Temperature Sensors
Product Information1 Specifications
- Power Supply : +18 to 40 Vdc or 24 Vac
- Output Signal : 4 to 20 mA, 0 to 5 Vdc, or 0 to 10 Vdc (field selectable)
- Humidity Range : 0 to 100% RH
- Temperature Sensor: 20K ohm NTC thermistor or 1K platinum PTC
Product Usage Instructions:
Installation
- Read the instructions carefully.
- Check the ratings to ensure suitability for your application.
- Installation must be done by a trained service technician.
- After installation, check the product operation.
Caution
Honeywell H7625A Humidity Temperature Sensors
Disconnect the power supply before installation to avoid electrical shock or equipment damage.
Installation Instructions
Caution
Improper wiring can damage the sensor. Follow the wiring instructions carefully.
Location
Install the sensor in a location where it cannot be affected by:
- Drafts, dead spots, or hot/cold air from ducts
- Radiant heat from sun or appliances
- Concealed pipes and chimneys
- Unheated (uncooled) areas such as an outside wall behind the device
Mounting
- Mount the housing base over a standard 2 in. x 4 in. single gang junction box or flush to the wall
- Install the sensor about 5 ft (1.5m) above the floor in an area with good air circulation at average humidity and temperature.
- Ensure the device receives adequate airflow.
- Wire the device according to the wiring diagram.
- Ensure proper DIP switch settings.
- Apply power to the unit.
- Snap the cover into position.
- Turn out the 1/16 in. allen screws at the bottom of the enclosure until the cover cannot be removed.
Output Settings
The humidity output signal can be adjusted for 0-5Vdc, 0-10 Vdc, or 4-20 mA using the switch block. Refer to Fig. 2 for switch settings.
FAQ
- Q: What is the power supply range for these sensors?
- A : The sensors can be powered with either +18 to 40 Vdc or 24Vac supply.
- Q: Can I adjust the humidity output signal?
- A : Yes, you can adjust the humidity output signal to 0-5Vdc, 0-10 Vdc, or 4-20 mA using the switch block.
- Q: What is the default temperature sensor used?
- A : The default temperature sensor used is a 1K platinum PTC compatible with the T775.
APPLICATION
The H7625A, H7626A, H7635A and H7636A Wall-Mount Humidity/Temperature Sensors
are universal Relative Humidity transmitters that can be powered with either a
+18 to 40 Vdc or 24 Vac supply. The devices are half wave rectified. The
transmitter also includes either a 20K ohm NTC thermistor or a 1K platinum PTC
(compatible with the T775) for optional temperature use.
The humidity sensors are designed with a field 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 output.
INSTALLATION
When Installing this Product…
- Read these instructions carefully. Failure to follow them could damage the product or cause a hazardous condition.
- Check ratings given in instructions and on the product to ensure the product is suitable for your application.
- Installer must be a trained, experienced service technician.
- After installation is complete, check out product operation as provided in these instructions.
CAUTION
Electrical Shock or Equipment Damage Hazard. Can shock individuals or short
equipment circuitry.
Disconnect power supply before installation.
INSTALLATION INSTRUCTIONS
CAUTION
Equipment Damage Hazard.
Improper wiring can damage the sensor beyond repair.
Follow the wiring instructions carefully.
Location
Install the device where it cannot be affected by:
- drafts, or dead spots behind doors and in corners.
- hot or cold air from ducts.
- radiant heat from sun or appliances.
- concealed pipes and chimneys.
- unheated (uncooled) areas such as an outside wall behind the device.
Mounting
The housing base mounts over standard 2 in. x 4 in. single gang junction box or flush to the wall:
- Install the sensor about 5 ft (1.5m) above the floor in an area with good air circulation at average humidity and temperature. (See Fig. 1.)
- Ensure the device receives adequate airflow.
- Wire the device. (See Fig. 5 through 4.)
- Ensure proper DIP switch settings.
- Apply power to the unit.
- Snap the cover into position.
- Turn out the 1/16 in. allen screws at the bottom of the enclosure until the cover cannot be removed.
Output Settings
The humidity output signal can be adjusted for 0-5Vdc, 0-10 Vdc or 4-20 mA
using the switch block. Switches 6, 7, and 8 are used to set the output.
NOTE : Refer to Fig. 2 for switch settings.
Table 1. Controller Compatibility and Output Settings.
REVERSE ACTING OUTPUT
The output can be changed to reverse acting mode. The output range stays the
same but the corresponding RH value is opposite. Direct Acting is the default
mode.
Example : Direct Acting (DA)
- 0-10V output mode
- 0V = 0% RH and 10V = 100% RH
Reverse Acting (RA)
- 0-10V output mode,
- 0V = 100% and 10V = 0%
To change the transmitter to reverse acting or back to direct acting, set
switch 4 ON to put the unit in setup mode. After switch 4 is on, switch 2 will
put the unit in direct/reverse-acting mode. When switch 2 is set to ON, the
output can be used to show if the unit is in direct or reverse acting mode.
For direct acting the output will be 1V for 0-5V, 2V for 0-10V, and 7.2mA for
4-20mA. For reverse acting the output will be 4V for 0-5V, 8V for 0-10V, and
16.8mA for 4-20mA.
With switches 2 and 4 ON, each time switch 5 is set to ON the output will
change to reverse acting or direct acting.
To reset the unit to the default setting, toggle both switches 5 and 6 ON then
OFF while both switches 2 and 4 are ON.
When all calibration is completed, remember to place the switches back into
the positions that correspond to the output needed as shown in Figure 3.
WIRING
A 16 to 22 AWG shielded cable is recommended for all transmitters. Twisted
pair may be used for 2-wire current output transmitters.
Refer to Figure 3 for wiring diagrams.
CAUTION
It is recommended that you use an isolated UL-listed class 2 transformer when powering the unit with 24 VAC. Failure to wire the devices with the correct polarity when sharing transformers may result in damage to any device powered by the shared transformer.
IMPORTANT
When using shielded cable, ground the shield only at the controller end (see Fig. 4). Grounding both ends can cause a ground loop.
CHECKOUT
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.
NOTE : Use laboratory quality meters and gauges for appli-cations requiring a high degree of accuracy.
- Verify that the transducer is mounted in the correct position.
- Verify appropriate input signal and voltage supply.
- Verify appropriate configuration range.
Converting Output Signal to Percent RH
4 to 20mA Signal
- ((mA signal) -4) / 0.16 = percent RH
- Example : 12mA output signal
- (12-4) / 0.16 = 50% RH
0 to 5 Vdc Signal
- (VDC signal) / 0.05 = percent RH
- Example : 1.25vdc output signal
- 1.25 / 0.05 = 25% RH
0 to 10 Vdc Signal
- (VDC signal) / 0.10 = percent RH
- Example : 7.50vdc output signal
- 7.50 / 0.10 = 75% RH
Table 2. Troubleshooting.
APPENDIX
RH Test and Configuration DIP Switch Settings (Table 3)
IMPORTANT
-
Only adjust these switches for troubleshooting or recalibrating the sensor.
(Adjustment is not normally necessary.) -
Test mode will make the transmitter output a fixed 0%, 50%, or 100% value. The sensor will not affect the transmitter output. This is used for troubleshooting or testing only.
-
Switches 1, 2, and 3 are used for test mode. The output will be a fixed 0%, 50%, or 100% signal that corresponds to the output selected with switches 6, 7, and 8. Refer to Figure 4 for switch settings.
Table 3. Test and Calibration Settings (8-Switch Block).
CALIBRATION
NOTE : This is only a single-point calibration. All transmitters are factory-calibrated to meet/exceed published specifications. Field adjustment should not be necessary.
The dipswitch allows the user to calibrate the sensor through the software.
Setting switch 4 ON will put the transmitter into setup mode allowing the
increment and decrement to work. Once in setup mode, the output will change to
50% (2.5V for 0-5V, 5V for 0-10V, 12mA for 4-20mA). Each increment or
decrement step will cause the output to change by 0.1V for 0-5V, 0.2V for
0-10V, and 0.32mA for 4-20mA in setup mode. This can be used to show the user
how far offset the transmitter is. To see the starting point again set switch
1 ON. This will show the 50% output again. When the unit is out of setup mode
the output will go back to RH output.
Increment RH Output
This will shift the RH output linearly up in 0.5% steps. Switch 4 must be set to ON first. After switch 4 is on, each time switch 5 is set ON the RH output will increase by 0.5%. The increase goes into effect each time switch 5 is set to ON.
Decrement RH Output
This will shift the RH output linearly down in 0.5% steps. Switch 4 must be
set to ON first. After switch 4 is on, each time switch 6 is set ON the RH
output will decrease by 0.5%. The decrease goes into effect each time switch 6
is set to ON.
Reset RH Output
This will reset the RH output back to the original calibration. Switch 4 must
be set to ON first. After switch 4 is on, toggle switches 5 and 6 ON then OFF.
After 5 and 6 are OFF slide switch 4 OFF.
When all calibration is completed, remember to place the switches back into
the positions that correspond to the output needed as shown in Figure 3.
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