General Assist Technical Reference
Input and Output Connections
Airstage J-IVS indoor units
External control inputs, status outputs and optional connection kits
Airstage J-IVS indoor units provide configurable low-voltage input and output connections for integration with switches, relays, thermostats, Building Management Systems (BMS) and auxiliary equipment. Available functions include operation/stop, emergency stop, forced stop, forced thermostat off, operating status, fault status, fan status and auxiliary heater output.
Important: Terminal availability, PCB layout and function-setting numbers can vary between indoor-unit models. Confirm the applicable installation or service manual before wiring. All work must be completed by appropriately qualified personnel with power isolated.
1. External input terminals
External inputs allow an indoor unit or refrigerant system to be controlled by a third-party device. The control input can use either an externally applied voltage or a voltage-free dry contact. The two input methods must not be used simultaneously on the same input.
| Function | Input Type | Connector | Key Requirement |
|---|---|---|---|
| Operation / Stop | Apply voltage or dry contact | CNA01 or CNA02 | Select the required function setting and Edge or Pulse input mode. |
| Emergency Stop | Apply voltage or dry contact | CNA01 or CNA02 | Stops all indoor units within the same refrigerant system. |
| Forced Stop | Apply voltage or dry contact | CNA01 or CNA02 | Remote-controller operation is restricted while forced stop is active. |
| Forced Thermostat Off | Dry contact only | CNA03 or CNA04 | Used to suspend thermostat demand while the unit remains under normal control logic. |
Apply-voltage input – CNA01 / CNA03
- External power supply: DC 12–24 V.
- Recommended input current: DC 5 mA. Allowable current: DC 10 mA or less.
- Do not apply more than 24 V across the specified terminals.
- Observe polarity: positive to pin 1 and negative to pins 2 and 3, as shown in the applicable wiring diagram.
- When one external supply operates multiple indoor units, branch the wiring outside the indoor units.
Dry-contact input – CNA02 / CNA04
- Use voltage-free, very-low-current contacts suitable for DC 12 V and DC 1 mA or less.
- Dry-contact wiring differs from apply-voltage wiring. Confirm the connector and pin arrangement before connection.
- When controlling multiple indoor units, isolate each indoor unit with an individual relay.
Do not connect one dry-contact input directly across multiple indoor units. Each unit must be electrically isolated using separate relay contacts to prevent PCB damage.
2. Input signal and control logic
Edge and Pulse selection
| DIP Switch SET2-2 | Input Mode | Application |
|---|---|---|
| OFF – Factory setting | Edge | Maintained contact. A change of contact state changes the command. |
| ON | Pulse | Momentary contact. Pulse width must be greater than 200 ms. |
Forced thermostat off: Channel 3 is Edge input only, regardless of the SET2-2 selection.
Control behaviour
- Operation / Stop: External commands start and stop the indoor unit. The latest valid command has priority.
- Emergency Stop: All indoor units in the same refrigerant system stop. Normal remote-controller operation resumes only after the emergency-stop state is reset.
- Forced Stop: The indoor unit stops and operation/stop control from the remote controller is restricted while the input remains active.
- Forced Thermostat Off: Thermostat demand is removed. Depending on fan settings and operating conditions, the indoor fan may continue to run.
When Forced Stop is used within a remote-controller group, apply the same command to every indoor unit in that group. Do not apply the command to only one unit within the group.
3. External output terminals
External outputs provide DC status signals from connector CNB01. Outputs may operate an indicator directly or energise an appropriately rated relay.
| Output Function | CNB01 Pins | Output State | Status Indicated |
|---|---|---|---|
| Operation Status | 1–2 | DC 12 V = ON 0 V = OFF | Indoor unit operating / stopped |
| Error Status | 1–3 | DC 12 V = Error 0 V = Normal | Indoor-unit fault present |
| Indoor Unit Fan Status | 1–4 | DC 12 V = Fan operating 0 V = Fan stopped | Indoor fan operation |
| Auxiliary Heater Output | 1–5 | DC 12 V = Heater command 0 V = OFF | Auxiliary heater demand |
Output circuit specifications
- Output voltage: DC 12 V at HIGH and 0 V at LOW.
- Maximum permissible current: 50 mA per output.
- Recommended cable: 0.33 mm² (22 AWG) twisted pair.
- Maximum cable length: 25 m.
- Use a relay when the connected load exceeds the permitted output rating.
Auxiliary heater safety: The CNB01 output is a control signal only. Install the heater through correctly rated switching, over-temperature protection and all other required electrical safety devices. Follow the indoor-unit manual and local regulations.
4. Optional connection kits
| Model | Application | Input / Output Type |
|---|---|---|
| UTY-XWZXZ7 | Forced thermostat off port | Apply-voltage terminal |
| UTY-XWZXZC | External output port | CNB01 output harness |
| UTY-XWZXZB | Control input port | Apply-voltage terminal |
| UTY-XWZXZD | Control input port | Dry-contact terminal |
| UTY-XWZXZE | Forced thermostat off port | Dry-contact terminal |
5. Wiring and commissioning guidance
- Confirm the indoor model. Check the model-specific installation or service manual for connector availability and PCB location.
- Isolate power. Do not connect or disconnect PCB harnesses while the unit is energised.
- Select the correct interface. Do not mix apply-voltage and dry-contact methods.
- Configure the function. Set the applicable function number and SET2-2 Edge/Pulse selection before testing.
- Use appropriate cable. The manual specifies 0.33 mm² (22 AWG) twisted cable. Keep control wiring separated from mains wiring.
- Observe distance limits. Maximum input wiring length is 150 m; maximum external-output wiring length is 25 m.
- Provide electrical isolation. Use separate relay contacts where one external controller operates multiple indoor units.
- Test every state. Confirm normal, active and reset behaviour from both the external device and the wired or wireless controller.
6. Quick reference
| Connection | Connector | Electrical Specification | Maximum Length |
|---|---|---|---|
| Control input – apply voltage | CNA01 | DC 12–24 V; 10 mA or less | 150 m |
| Control input – dry contact | CNA02 | Voltage-free contact; DC 12 V, 1 mA or less | 150 m |
| Forced thermostat off | CNA03 / CNA04 | Dry-contact interface shown in the function summary; confirm model manual | 150 m |
| Status outputs | CNB01 | DC 12 V; 50 mA or less per output | 25 m |
Reference: Airstage J-IVS external input/output technical information, indoor-unit section, pages 08-8 to 08-25. Always verify against the latest model-specific documentation.