Isolated Analog Signal Converter J Type
Isolated Analog Signal Converter J Type AC-TCJ-420
The AC-TCJ-420 is an industrial DIN-rail thermocouple transmitter engineered to convert low-millivolt signals from Type J (Iron-Constantan) thermocouples into an isolated standard analog signal (4–20mA, 0–20mA, or 0–10V DC). Featuring built-in precision Cold Junction Compensation (CJC) and sensor burnout alarm detection, it delivers highly accurate and linear temperature measurements across standard industrial temperature spans up to +750 °C. Engineered with 3-way galvanic isolation (1,500V AC across input, output, and power supply), it eliminates hazardous ground loops, suppresses heavy electrical noise, and protects downstream PLCs and control systems in plastics, packaging, and vulcanization environments.
Key Features
- 3-way 1.5 kV AC galvanic isolation (input, output, and power)
- Type J thermocouple input (Iron-Constantan)
- Internal cold junction compensation (CJC)
- Factory customizable temperature spans across -40 °C to +750 °C
- 4–20mA active current loop output driving loads up to 500 Ω
- Fast response time (≤ 10 ms) for furnace and thermal control
- Sensor burnout protection with visual alarm indicator (
ALM) - 24V DC industrial power supply input
- Slim 25 mm DIN rail mountable housing
- Dimensions: 110 mm × 47 mm × 25 mm
Ordering Information
| Product Code | Description |
|---|---|
| AC-TCJ-420 | Isolated Thermocouple Converter J-Type to 4–20mA (24V DC, 3-Way Isolated) |
| AC-TCK-420 | Isolated Thermocouple Converter K-Type to 4–20mA (24V DC, 3-Way Isolated) |
| AC-PT100-420 | Isolated Analog Signal Converter Pt 100 (4–20mA, 24V DC, 3-Way Isolated) |
| AC-PT1000-420 | Isolated Analog Signal Converter Pt 1000 (4–20mA, 24V DC, 3-Way Isolated) |
| AC-RES-420 | Isolated Resistance Signal Converter 0–5k \(\Omega\) to 4–20mA |
| SPD-20MA | 4–20mA Surge Protection Device |
| USS20M24V-D | Current Source Simulator 0/4 to 20mA with Display |
Applications
- Plastics Extrusion & Injection Molding: Precision temperature monitoring in extruder barrels, dies, and hot runner nozzles.
- Rubber & Tire Vulcanization: Controlling mold temperatures and curing presses.
- Packaging Machinery & Heat Sealers: Monitoring sealing jaw and shrink-wrap heating elements.
- Commercial & Industrial Ovens: Conveyor curing ovens, powder coating lines, and baking equipment.
- Hydraulic Oil & Machinery Systems: Bearing and hydraulic fluid temperature tracking in non-oxidizing atmospheres.
Specifications
| Parameter | Value |
|---|---|
| Mounting Type | 35 mm DIN Rail Mounting |
| Dimensions | 110 mm x 47 mm x 25 mm (L x H x W) |
| Weight | 100 g |
| Enclosure Material | Industrial Grade ABS |
| Operating Temperature | -20 °C to +55 °C |
| Storage Temperature | -40 °C to +85 °C |
| Relative Humidity | 5% to 95% RH (non-condensing) |
Electrical Specifications
| Parameter | Specification |
|---|---|
| Power Supply Voltage | 24V DC \(\pm 10\%\) |
| Operating Current | 100 mA @ 24V DC |
| Sensor Input Type | Type J Thermocouple (Iron-Constantan, Fe-CuNi) |
| Cold Junction Compensation | Integrated internal precision CJC |
| Temperature Range | Customizable from -40 °C to +750 °C |
| Measurement Accuracy | Class 0.2% of Full Scale @ 25 °C (1–2 °C) |
| Output Signal Range | 4.00 mA to 20.00 mA (or 0–20 mA / 0–10V DC on request) |
| Maximum Output Load Resistance | \(R_L \le 500\,\Omega\) |
| Response Time | \(\le 10\text{ ms}\) (0–90% TYP) |
| Galvanic Isolation Barrier | 1,500 V AC / 1 min (3-Way: Input / Output / Power Supply) |
| Status Indicators | PWR LED (Power ON), ALM LED (Thermocouple Burnout / Open Circuit) |
| Burnout Protection | Upscale / Downscale burnout output drive |
| Reverse Polarity Protection | Integrated diode on 24V DC input |
Mechanical Dimensions
Terminal Details & Wiring
Connection Pinouts
| Terminal Block | Pin | Label | Signal | Description |
|---|---|---|---|---|
| Input Terminals | 1 | SLD | Shield | Thermocouple extension cable shield (Earth ground) |
| (Top Block) | 2 | NC | No Connection | Reserved / Not Connected |
| 3 | TC + | Positive Input | Type J Positive Lead (Iron / White or Black wire) | |
| 4 | TC - | Negative Input | Type J Negative Lead (Constantan / Red or White wire) | |
| Output Terminals | 5 | OUT + | Signal Out (+) | Active 4–20mA Analog Output (+) |
| (Bottom Block) | 6 | OUT - | Signal Out (-) | Analog Signal Ground / Current Return (-) |
| Power Terminals | 7 | PWR + | 24V DC (+) | +24V DC Operating Power Supply |
| (Bottom Block) | 8 | PWR - | 0V DC (-) | Power Supply Ground Return |
Sensor Wiring Configuration
- Connect the positive thermocouple lead (Iron) to terminal
3(TC +). - Connect the negative thermocouple lead (Constantan) to terminal
4(TC -). - If using shielded thermocouple extension cable, connect the drain wire/shield to terminal
1(SLD) for electrical noise suppression. - Internal cold junction compensation eliminates the need for an external reference junction.
LED Indications and Diagnostics
| LED | Color | Status | Description |
|---|---|---|---|
| PWR | Green | ON | Normal 24V DC operating power connected |
| ALM | Red | OFF | Normal operation; sensor input within valid range |
| ALM | Red | ON | Sensor open-circuit, broken wire, or burnout detected |
Revision History
| Revision | Date | Description of Change |
|---|---|---|
| Rev 1.0 | 2026-09-09 | Initial datasheet release |
Get the latest version of this datasheet : click here..
Support
Website: www.veawe.io
Email: info@veawe.io