Distech Controls HS-THX User manual

Installation Guide
HS-THX
Analog Horticulture Sensor -Temperature, Humidity
Figure 1: HS-THX Analog Horticulture Sensor
Product Description
This document describes the hardware installation procedures for the HS-THX Analog Horticulture Sensor.
The horticulture sensor series uses a precision thermistor to monitor temperature and a thermoset polymer based capacitance sensor to measure humidity
levels. Features include a LCD for configuration and monitoring, various output signal types, optional relays for alarm indication and field replaceable
sensors.
General Installation Requirements
For proper installation and subsequent operation of each device, pay special attention to the following recommendations:
- Upon unpacking the product, inspect the contents of the carton for shipping damages. Do not install damaged device.
- Avoid areas where corroding, deteriorating or explosive vapors, fumes or gases may be present.
- Ensure that all equipment is installed according to local, regional, and national regulations.
Personal injury or loss of life may occur if you do not follow a procedure as specified.
Equipment damage or loss of data may occur if you do not follow a procedure as specified.
Take reasonable precautions to prevent electrostatic discharges to the controller when installing, servicing or operating
the controller. Discharge accumulated static electricity by touching one’s hand to a well-grounded object before working
with the controller.

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Mounting Instructions
Remove the cover by using a standard or flat screwdriver to loosen the four screws as shown in Figure 2.
Complete removal of the screw from the cover is not required as the screws are captive type. The horticulture sensor can be mounted directly onto any
wall or flat surface, or may be suspended from the ceiling using the device cable harness which is secured to the enclosure with a compression style
fitting.
Figure 2: Loosening enclosure screws.
For wall mounting, select a suitable mounting area away from opening windows or doors and avoid areas subject to high vibrations or excessive moisture.
Mount the device directly to the flat surface using the four integrated mounting holes that are provided on each corner of the enclosure using #8 size
screws (not provided). Ensure the sensor pods are pointing downwards as shown in Figure 3.
Figure 3: Wall mounting using size #8 screws.
After the enclosure is securely mounted to the wall, feed the cable through the cable gland and securely tighten the compression fitting as shown in Figure
4. It is generally easier to prepare the cable by stripping sufficient jacket and wires before feeding the cable through the cable gland.
Figure 4: Feeding the cable through the cable gland
For a hanging style mount, feed the cable through the cable gland and securely tighten the compression fitting as shown in Figure 4. Ensure the cable
is also securely fastened to the ceiling mount and that the cable length is sufficient for the required location.

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Make wiring connections as per the "Wiring" illustrations. Once the wiring and device setup are complete, re-install the cover and secure with the four
screws as shown in Figure 5.
Figure 5: Closing the enclosure.
Wiring
Deactivate the 24 Vac/dc power supply until all connections are made to the device to prevent electrical shock or equipment damage. Follow proper
electrostatic discharge (ESD) handling procedures when installing the device or equipment damage may occur. Use 14-22 AWG shielded wire for all
connections and do not locate the device wires in the same conduit with wiring used to supply inductive loads
such as motors. Pull at least six inches of wire into the enclosure and complete the wiring connection according to the wiring diagram. Make all connections
in accordance with national and local codes.
Connect the plus DC or the AC voltage hot side to the POWER terminal and the power supply common is connected to the COMMON terminal. The
device is reverse voltage protected and will not operate if connected backwards. It has a half-wave power supply so the supply common is the same as
the signal common. Use caution when wiring multiple devices or when grounding the secondary of a transformer to ensure that the circuit ground point
is the same on all devices and the controller.
The analog outputs are available on the TEMP and RH terminals. The signal type may be ordered as either voltage or 4-20 mA active outputs. The
voltage model is selectable for either 0-5 or 0-10 Vdc via the menu (the factory default is 0-5 Vdc). The current outputs operate in the active mode and do
not require a loop power supply. This means that the signal current is generated by the horticulture sensor and the outputs must not be connected to a
powered input or device damage will result. Check the controller Analog Inputs (AI) to determine proper connection before applying power. Both current
and voltage output signals are referenced to the COMMON terminal. The analog output signals are typically connected directly to the Building Automation
System (BAS) and used as control parameters.
The horticulture sensor may have one or two optional relays installed. The relays are Form C type with both a normally open (NO) and a normally closed
(NC) contact. The relay contacts may be connected to controller Digital Inputs (DI) for status monitoring or used to directly control an alarm or ventilation
fan. Do not exceed the device contact ratings. In some cases a separate control relay may be used between the horticulture sensor relay and a large fan
for example.
Relay terminals are designated NO, COM and NC. Each relay output is independent and isolated from the other and the relays COMs are not connected
to the device COMMON.
Typical wiring diagrams are shown in Figure 6.
Figure 6: Wire Termination for Thermistor.

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Operation - Start-up - Analog
After applying power to the device, it will enter the start-up mode and the LCD will indicate the software version number and the output signal type for two
seconds each. Then the device will start normal operation.
Operation - Normal
During normal operation, the installed sensor measurements are read and displayed on the LCD. The analog outputs are updated with the appropriate
values and alarm conditions are monitored.
The relative humidity output signal is scaled 0-100 %RH = 4-20 mA or 0-5 Vdc depending on the device model. For the voltage output model, the output
signal may be changed to 0-10 Vdc by using the Setup Menu.
The temperature output signal is scaled 0-50 °C = 4-20 mA or 0-5/0-10 Vdc depending on the device model. The temperature range may be changed to
32-122 °F via the Setup Menu.
If the model also includes a carbon dioxide sensor, then the output signal is scaled 0-2000 ppm = 4-20 mA or 0-5/0-10 Vdc as above. If required, the CO2
scale can be changed via the Setup Menu to span values up to 5000 ppm.
The sensor readings are also displayed on the LCD depending on the device model and can also be configured with the Setup Menu. There are several
configurations on how information is displayed, see the Menu section for full details. Example displays are shown below.
Operation - Alarms
The device may also have one or two alarm relays installed, depending on the model. Each relay may operate as a high or low alarm and may be assigned
to either RH or temperature. For each alarm assignment, there are default values for the setpoints, hysteresis and time delay. The default values may be
changed within limits as required using the Setup Menu. The details of each setting and operation is explained in the Setup Menu section.
Operation - Setup Menu
The Setup Menu has several items as shown below. To enter the menu, press and release the <MENU> key while in normal operation. This will enter the
Setup Menu step 1, pressing the <MENU> key a second time advances to step 2. Each press of the <MENU> key saves the selection and advances the
menu item.
The <UP> and <DOWN> keys are used to make changes to program variables by scrolling through the available options.
<MENU> Press and release the <MENU> key to enter the Setup Menu
1. Temperature Scale
The temperature scale defaults to Celsius (°C). Use <UP> or <DOWN> to change to Fahrenheit (°F).
<MENU> Press to save and advance.
2. Temperature Offset
This item allows calibration of the temperature sensor. Use <UP> or <DOWN> to add an offset to the temperature
measurement. Use <MENU> to save and advance. -1 subtracts 1 degree from the temperature and +1 adds 1 degree
to the temperature. The range is –10 to +10 °F or -5.0 to +5.0 °C. Resolution is 1 °F or 0.5 °C. Units depends on the
previous C/F setting and resets to 0° if C/F is changed.
<MENU> Press to save and advance.
3. Humidity Offset
This item allows calibration of the RH sensor. Use <UP> or <DOWN> to add an offset to the RH measurement. Press
<MENU> to save and advance. -1 subtracts 1 %RH and +1 adds 1 %RH. The range is –10 to +10 %RH.
<MENU> Press to save and advance.

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Only if Relay 1 installed
4. Alarm 1
Alarm1 assignment defaults to Temp High Alarm. Use <UP> or <DOWN> to change to Temp Low, RH High or RH
Low as required. If the product has the optional relays, then Alarm1 controls Relay1 and Alarm2 controls Relay2.
<MENU> Press to save and advance.
5. Alarm 1 Setpoint
The Alarm1 setpoint depends on the Alarm1 assignment set previously as shown in the table. Use <UP> or <DOWN>
to change the setting within the limits. Note that a high alarm activates when the measurement exceeds the setpoint
and a low alarm activates when the measurement goes below the setpoint.
Alarm 1 Assignment
Default Setpoint
Setpoint Range
Resolution
Temp Hi
30°C / 86°F
10 to 40°C / 50 to 104°F
1°
Temp Low
15°C / 59°F
10 to 40°C / 50 to 104°F
1°
RH High
70 %RH
20 to 90 %RH
5 %RH
RH Low
40 %RH
20 to 90 %RH
5 %RH
<MENU> Press to save and advance.
6. Alarm 1 Hysteresis
The Alarm1 hysteresis depends on the Alarm1 assignment set previously as shown in the table. Use <UP> or
<DOWN> to change the setting within the limits. Note that a high alarm resets when the measurement goes below
(setpoint - hysteresis) and a low alarm resets when the measurement goes above (setpoint + hysteresis).
Alarm 1 Assignment
Default Hysteresis
Hysteresis Range
Resolution
Temp Hi or Low
2°C / 4°F
1 to 5°C / 2 to 10°F
1°
RH High or Low
10 %RH
5 to 20 %RH
1 %RH
<MENU> Press to save and advance.
7. Alarm 1 Delay
The Alarm1 Delay default is 15 seconds. This is the delay time after alarm conditions are met before an actual alarm
is set. This can be used to prevent false alarms. Use <UP> or <DOWN> to change the setting from 0 to 255 seconds.
<MENU> Press to save and advance.
Only if Relay 2 installed
8. Alarm 2 Assignment
Alarm2 assignment defaults to Temp Hi. Use <UP> or <DOWN> to change to Temp Low, RH High or RH Low as
required. If the product has the optional relays, then Alarm1 controls Relay1 and Alarm2 controls Relay2.
<MENU> Press to save and advance.
9. Alarm 2 Setpoint
The Alarm2 setpoint depends on the Alarm2 assignment set previously as shown in the table. Use <UP> or <DOWN>
to change the setting within the limits. Note that a high alarm activates when the measurement exceeds the setpoint
and a low alarm activates when the measurement goes below the setpoint.
Alarm 1 Assignment
Default Setpoint
Setpoint Range
Resolution
Temp Hi
30°C / 86°F
10 to 40°C / 50 to 104°F
1°
Temp Low
15°C / 59°F
10 to 40°C / 50 to 104°F
1°
RH High
70 %RH
20 to 90 %RH
5 %RH
RH Low
40 %RH
20 to 90 %RH
5 %RH
<MENU> Press to save and advance.

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10. Alarm 2 Hysteresis
The Alarm2 hysteresis depends on the Alarm2 assignment set previously as shown in the table. Use <UP> or
<DOWN> to change the setting within the limits. Note that a high alarm resets when the measurement goes below
(setpoint - hysteresis) and a low alarm resets when the measurement goes above (setpoint + hysteresis).
Alarm 1 Assignment
Default Hysteresis
Hysteresis Range
Resolution
Temp Hi or Low
2°C / 4°F
1 to 5°C / 2 to 10°F
1°
RH High or Low
10 %RH
5 to 20 %RH
1 %RH
<MENU> Press to save and advance.
11. Alarm 2 Delay
The Alarm2 Delay default is 15 seconds. This is the delay time after alarm conditions are met before an actual alarm
is set. This can be used to prevent false alarms. Use <UP> or <DOWN> to change the setting from 0 to 255 seconds.
<MENU> Press to save and advance.
Only if Output is Voltage
12. Out Type
The default analog output type is 0-5 Vdc. Use <UP> or <DOWN> to change to 0-10 Vdc if required. Use caution that
the selected output signal type matches the controller analog input.
<MENU> Press to save and advance.
13. Display Information
Use <UP> or <DOWN> to set the LCD display information to All, RH, Temp, RH-Temp, or None. All means RH/T.
None means no measurements are normally displayed but the start-up mode and menus are still displayed. The
factory default is All.
<MENU> Press to save and advance.
14. Backlight
Use <UP> or <DOWN> to set the LCD backlight to On, Off or Auto. When On the LCD backlight is always on, when
Off it never lights and if set to Auto it lights for a time period (30 seconds) whenever a key is pressed. Even if set to
Off, the backlight will light during the start-up mode. In Auto mode, the backlight will remain lit whenever a menu ssis
open. The factory default is Auto.
<MENU> Press to save and advance.

©, Distech Controls 2020 All rights reserved.
While all efforts have been made to verify the accuracy of information in this manual, Distech Controls is not responsible for damages or claims arising from the use of this
manual. Persons using this manual are assumed to be trained HVAC specialist / installers and are responsible for using the correct wiring procedures and maintaining safe
working conditions with fail-safe environments. Distech Controls reserves the right to change, delete or add to the information in this manual at any time without notice.
Distech Controls, the Distech Controls logo, and Innovative Solutions for Greener Buildings are trademarks of Distech Controls. All other trademarks are property of their
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Dimensions