IN-4 converts four independent 9–30V DC field signals into clean, active-high logic outputs for Arduino, ESP32, STM32, Raspberry Pi and similar controllers. Each input uses polarity-independent wiring, an optocoupler and Schmitt-trigger signal conditioning.
First-production rework disclosure
Reworked and individually function-tested. Minor cosmetic discoloration may be visible near the corrected components. This does not affect electrical performance. Each unit is tested before shipment.
Ships from Texas · 30-day returns · One-year KI Maker limited warranty · Checkout through eBay
Industrial sensors, PLC outputs, alarm contacts and machine signals commonly operate at 12V or 24V DC, while controller GPIO pins typically operate at only 3.3V or 5V. Those field voltages must never be connected directly to a GPIO pin. IN-4 provides a purpose-built interface between the two voltage domains.
Connect a 9–30V DC field signal across the corresponding INxA and INxB screw terminals. The onboard bridge rectifier allows either input-wire polarity. When field voltage is present, the channel optocoupler activates and the Schmitt-trigger logic produces a clean HIGH signal at the corresponding OUTx pin.
Connect the external 9–30V DC signal across the channel's two field-input terminals in either polarity.
The bridge, protection network, optocoupler and Schmitt-trigger stage convert the field state into a stable logic state.
The matching OUT pin goes HIGH at the supplied VLOGIC level when the field input is active and returns LOW when it is absent.
| Field condition | Channel LED | Corresponding OUTx |
|---|---|---|
| No field voltage | OFF | LOW |
| 9–30V DC present | ON | HIGH at the supplied VLOGIC level |
Never connect field voltage to H1 or directly to a controller GPIO pin.
H1 is the low-voltage logic interface. It accepts only the user-supplied 3.3V or 5V VLOGIC rail, logic ground and the four OUT signals. Field wiring belongs only on the IN1–IN4 screw terminals.
These values are a product-selection summary. Review the current specification sheet and owner's manual for complete wiring, operating and environmental requirements.
| Function | Published specification |
|---|---|
| Field inputs | Four independent two-wire DC inputs: IN1 through IN4. |
| Field-input voltage | 9–30V DC. Intended for common 12V and 24V DC control signals. |
| Input polarity | Polarity-independent. INxA and INxB may be connected in either DC polarity. |
| Logic supply | User-supplied 3.3V or 5V connected to H1 VLOGIC and logic ground. |
| Logic outputs | OUT1 through OUT4. Active-high digital signals intended for controller GPIO inputs. |
| Output HIGH level | Follows the supplied 3.3V or 5V VLOGIC rail. |
| Output with no field input | LOW. |
| Field-to-logic isolation | One LTV-817S optocoupler per channel provides functional separation between the field and logic signal paths. |
| Input protection | Per-channel bridge rectifier and bidirectional transient-voltage suppression device. |
| Output conditioning | SN74HC14 Schmitt-trigger logic with series output protection. |
| Connections | 5.0mm screw-terminal field inputs and a standard 2.54mm logic header. |
The following measurements were recorded on UUT-02 from first-production Lot 2608-01 using the KI Maker PWR INTF R&D board, a JESV supply and a Fluke digital multimeter. They document representative unit behavior; the published limits above remain the product specification.
| Test condition | OUT1 | OUT2 | OUT3 | OUT4 |
|---|---|---|---|---|
| 3.3V VLOGIC, active field inputs | 3.262V | 3.260V | 3.261V | 3.258V |
| 5V VLOGIC, active field inputs | 4.95V | 4.95V | 4.95V | 4.95V |
| No field-input voltage, either VLOGIC setting | 0V | 0V | 0V | 0V |
All reported measurements were stable at the time of observation.
KI Maker publishes the information needed to evaluate and use IN-4. The product-page values are summaries; the current controlled documents remain the detailed reference.
Yes, when the sensor output and IN-4 are wired within the published 9–30V DC field-input requirements. Supply IN-4 with 3.3V VLOGIC so its active-high outputs match the controller's 3.3V GPIO system.
Yes. Supply the H1 VLOGIC input with 5V and the active OUT signals will follow that logic-supply level.
No. Each field channel uses a bridge rectifier, so INxA and INxB may be connected in either DC polarity within the published input range.
A dry contact does not supply voltage. Use the contact with an appropriate external 9–30V DC source so opening and closing the contact removes or applies voltage across the selected IN-4 channel.
No. They are protected logic signals intended for controller GPIO inputs. Use a suitable output driver such as KI Maker OUT-4 for compatible low-voltage DC loads.
No. The optocouplers provide functional field-to-logic separation only. IN-4 is not certified for safety, emergency-stop, SIL, PL, medical or fail-safe functions.
Use one 18–30V DC supply to provide regulated 12V, 5V and 3.3V rails plus documented controller interfaces.
Available now · $37.50
Switch compatible 12V and 24V DC loads from four controller outputs within the published current limits.
Available now · $19.95
IN-4 is developed by KI Maker, a product brand of Kuster Induction Solutions LLC. It is supplied as an assembled, clearly labeled four-channel field-input interface with published operating limits, supporting documentation and individual functional testing before shipment.
IN-4 converts four independent 9–30V DC field signals into clean, active-high logic outputs for Arduino, ESP32, STM32, Raspberry Pi and similar controllers. Each input uses polarity-independent wiring, an optocoupler and Schmitt-trigger signal conditioning.
First-production rework disclosure
Reworked and individually function-tested. Minor cosmetic discoloration may be visible near the corrected components. This does not affect electrical performance. Each unit is tested before shipment.
Ships from Texas · 30-day returns · One-year KI Maker limited warranty · Checkout through eBay
Industrial sensors, PLC outputs, alarm contacts and machine signals commonly operate at 12V or 24V DC, while controller GPIO pins typically operate at only 3.3V or 5V. Those field voltages must never be connected directly to a GPIO pin. IN-4 provides a purpose-built interface between the two voltage domains.
Connect a 9–30V DC field signal across the corresponding INxA and INxB screw terminals. The onboard bridge rectifier allows either input-wire polarity. When field voltage is present, the channel optocoupler activates and the Schmitt-trigger logic produces a clean HIGH signal at the corresponding OUTx pin.
Connect the external 9–30V DC signal across the channel's two field-input terminals in either polarity.
The bridge, protection network, optocoupler and Schmitt-trigger stage convert the field state into a stable logic state.
The matching OUT pin goes HIGH at the supplied VLOGIC level when the field input is active and returns LOW when it is absent.
| Field condition | Channel LED | Corresponding OUTx |
|---|---|---|
| No field voltage | OFF | LOW |
| 9–30V DC present | ON | HIGH at the supplied VLOGIC level |
Never connect field voltage to H1 or directly to a controller GPIO pin.
H1 is the low-voltage logic interface. It accepts only the user-supplied 3.3V or 5V VLOGIC rail, logic ground and the four OUT signals. Field wiring belongs only on the IN1–IN4 screw terminals.
These values are a product-selection summary. Review the current specification sheet and owner's manual for complete wiring, operating and environmental requirements.
| Function | Published specification |
|---|---|
| Field inputs | Four independent two-wire DC inputs: IN1 through IN4. |
| Field-input voltage | 9–30V DC. Intended for common 12V and 24V DC control signals. |
| Input polarity | Polarity-independent. INxA and INxB may be connected in either DC polarity. |
| Logic supply | User-supplied 3.3V or 5V connected to H1 VLOGIC and logic ground. |
| Logic outputs | OUT1 through OUT4. Active-high digital signals intended for controller GPIO inputs. |
| Output HIGH level | Follows the supplied 3.3V or 5V VLOGIC rail. |
| Output with no field input | LOW. |
| Field-to-logic isolation | One LTV-817S optocoupler per channel provides functional separation between the field and logic signal paths. |
| Input protection | Per-channel bridge rectifier and bidirectional transient-voltage suppression device. |
| Output conditioning | SN74HC14 Schmitt-trigger logic with series output protection. |
| Connections | 5.0mm screw-terminal field inputs and a standard 2.54mm logic header. |
The following measurements were recorded on UUT-02 from first-production Lot 2608-01 using the KI Maker PWR INTF R&D board, a JESV supply and a Fluke digital multimeter. They document representative unit behavior; the published limits above remain the product specification.
| Test condition | OUT1 | OUT2 | OUT3 | OUT4 |
|---|---|---|---|---|
| 3.3V VLOGIC, active field inputs | 3.262V | 3.260V | 3.261V | 3.258V |
| 5V VLOGIC, active field inputs | 4.95V | 4.95V | 4.95V | 4.95V |
| No field-input voltage, either VLOGIC setting | 0V | 0V | 0V | 0V |
All reported measurements were stable at the time of observation.
KI Maker publishes the information needed to evaluate and use IN-4. The product-page values are summaries; the current controlled documents remain the detailed reference.
Yes, when the sensor output and IN-4 are wired within the published 9–30V DC field-input requirements. Supply IN-4 with 3.3V VLOGIC so its active-high outputs match the controller's 3.3V GPIO system.
Yes. Supply the H1 VLOGIC input with 5V and the active OUT signals will follow that logic-supply level.
No. Each field channel uses a bridge rectifier, so INxA and INxB may be connected in either DC polarity within the published input range.
A dry contact does not supply voltage. Use the contact with an appropriate external 9–30V DC source so opening and closing the contact removes or applies voltage across the selected IN-4 channel.
No. They are protected logic signals intended for controller GPIO inputs. Use a suitable output driver such as KI Maker OUT-4 for compatible low-voltage DC loads.
No. The optocouplers provide functional field-to-logic separation only. IN-4 is not certified for safety, emergency-stop, SIL, PL, medical or fail-safe functions.
Use one 18–30V DC supply to provide regulated 12V, 5V and 3.3V rails plus documented controller interfaces.
Available now · $37.50
Switch compatible 12V and 24V DC loads from four controller outputs within the published current limits.
Available now · $19.95
IN-4 is developed by KI Maker, a product brand of Kuster Induction Solutions LLC. It is supplied as an assembled, clearly labeled four-channel field-input interface with published operating limits, supporting documentation and individual functional testing before shipment.