ROPEX RES-402 Temperature Controller

Marca: ROPEX, Alemania

Product Definition: Sensorless resistive impulse heat-sealing temperature controller (No thermocouple required! Temperature is calculated by detecting resistance variation of the heat-sealing band itself.)

Solicitud: Control heat-sealing bands, sealing blades, hot cutting wires and thermal welding elements, widely adopted for impulse heat-sealing processes on bag-making machines and packaging equipment.

⚠️ Important Notice: RES-402 has been officially declared obsolete. Supplies mainly consist of new surplus stock and used refurbished units. Recommended upgraded alternatives: RES-420 / RES-430 / RES-5010.

2. Codificación de modelos & Order Number Breakdown

Formato de modelo completo: RES-402/Supply Voltage

3. Especificaciones técnicas clave
4. Temperature Measurement Principle: Passive resistance detection (thermocouple-free)
5. Temperature Measuring Range: 0～300 °C (Matched with A20 alloy heat-sealing band)
6. Adaptación de carga (AUTORANGE Auto-Ranging Function)

Transformer secondary voltage: 0.4～80 VAC

Secondary current: 30A～500A

4. Montaje: DIN TS35 standard rail mounting

Overall dimension: W90mm × D75mm × H135mm (including terminals)

5. Fuente de alimentación auxiliar: 24VCC (Terminales 13/14), máx.. 1A, reverse-polarity protection

(Must be powered independently and galvanically isolated from main power circuit)

6. Comunicación & Analog Interfaces (Electrically Isolated)

Setpoint input: 0～10VDC or external PD-3 potentiometer

Actual temperature output: 0～10VDC (0–300℃ corresponds linearly to 0–10V, for PLC acquisition)

7. Digital Control Signals (24VDC Isolated Input)

START (Heating enable), AUTOCAL (Automatic calibration), REINICIAR (Fault reset)

8. Grid Frequency Adaptation: Auto detection for 47～63Hz mains frequency
9. Funciones de protección: Heat-sealing band breakage detection, overtemperature alarm, fault relay output with LED indicator
10. Built-in Core Functions

AUTOCAL Automatic Zero Calibration: One-touch baseline resistance calibration after startup or heat band replacement

AUTOTUNE PID Self-Tuning: Automatically adapt to thermal capacity of heat-sealing bands to suppress temperature overshoot

AUTORANGE: Automatic detection of transformer secondary voltage and current; no manual DIP switch setting (Units manufactured from 2006 onwards)

Closed-loop primary-side phase-angle regulation for the transformer with low power loss

5. Escenarios de aplicación típicos

Impulse heat sealing on plastic bag machines, vertical form-fill-seal machines and horizontal flow wrappers

Heat sealing for PE/PP composite films and aluminium foil pouches

Hot film cutting, thermal edge sealing and catheter heat-sealing processes

Heat-sealing stations for lithium-ion battery flexible packaging

6. Pautas de cableado (Condensed Version)
7. Main Circuit LINE: Connect to AC main power as marked on the controller nameplate (115/230/400V)
8. Terminales 13 & 14: Independent external 24VDC auxiliary power supply is mandatory (powers all signal circuits)
9. The pulse transformer primary winding is driven by RES-402; secondary winding directly connects to the heat-sealing band
10. Analog signals: 15(+) / 12(-) setpoint input; 11(+) / 12(-) actual temperature feedback output
11. 16 START, 17 AUTOCAL, 18 REINICIAR: Triggered by 24VDC high level
12. ALARM terminals: Passive fault output for PLC alarm signal collection

✅ Wiring Recommendation: Use twisted pair cables for secondary wiring of heat-sealing bands to reduce electromagnetic interference; reliably ground transformer secondary side to avoid electrostatic drift.

7. Alternative Models for Obsolete Upgrade
8. Direct functional replacement (Minimum modification required): RES-420
9. Intelligent upgrade with fieldbus (Profinet/Modbus): RES-5010
10. Notas de reemplazo: Verify supply voltage, transformer specifications and logic of PLC analog signals & E/S digitales.
11. Quick Troubleshooting
12. ALARM LED steady on, heating disabled: Broken heat-sealing band or open secondary circuit
13. Persistently low temperature, unstable control: AUTOCAL not executed, insufficient transformer capacity
14. Severe temperature oscillation and overshoot: Re-run AUTOTUNE self-tuning
15. Controller completely unresponsive: Inspect independent 24VDC auxiliary power supply

(Common oversight! The unit cannot operate with main LINE power only.)

Detailed Explanation of AUTORANGE (Automatic Load Ranging Function) for ROPEX RES‑402

Critical Preliminary Clarification

AUTORANGE ≠ AUTOCAL

AUTORANGE: Detect transformer secondary voltage U₂ and secondary current I₂, automatically configure hardware measurement ranges (hardware gain matching)

AUTOCAL: Collect baseline resistance of cold heat-sealing band at ambient temperature, establish resistance ↔ temperature conversion curve (temperature zero calibration)

The two functions work collaboratively yet remain independent.

Production Version Boundary (Key Information for Procurement & Mantenimiento)

1. RES‑402 manufactured before December 2005: No AUTORANGE

Internal DIP switches must be manually adjusted to set secondary voltage and current ranges. Incorrect switch settings cause measurement failure and alarms.

2. RES‑402 manufactured from January 2006 onwards: AUTORANGE equipped

DIP switch configuration is overridden by firmware. No manual range setup required. Load electrical parameters are automatically identified during AUTOCAL procedure.

1. Official Definition of AUTORANGE

Full name: Automatic configuration of secondary voltage and current ranges

Automatically detect secondary voltage U₂ and output current I₂ of pulse transformer, dynamically select internal voltage sampling circuit and current transformer amplification gain. This ensures measurement circuits operate within optimal accuracy range and enables wide load compatibility.

Official Rated Load Coverage (New Version)

Transformer secondary open-circuit / operating voltage U₂: 0.4 VAC ～ 80 VACACIONES

Transformer secondary operating current I₂: 30 A ～ 500 A

Simplified explanation: A single RES‑402 unit can drive low-power narrow sealing bands (bajo voltaje, tens of amperes) as well as wide, long high-power sealing blades (high voltage, hundreds of amperes). No controller replacement or internal switch adjustment needed.

2. Underlying Operating Principle

RES‑402 is a thermocouple-free resistive impulse heat-sealing controller. Temperature is calculated continuously based on resistance variation of the heat-sealing band.

To accurately measure band resistance, the controller simultaneously samples two signals:

1. Secondary voltage signal Ur of pulse transformer
2. Secondary loop current signal Ir

Instantaneous resistance of the heat-sealing band is calculated via Ohm’s Law: R = Ur / Y.

Multiple sets of hardware voltage dividers and amplifier circuits are integrated internally. Different U₂/I₂ levels require matched amplification ranges.

AUTORANGE Execution Sequence & Momento

1. Controller completes power-on self-test (Wait ≥10s)
2. Confirm START signal is OFF and heat-sealing band cools down to ambient temperature
3. User triggers AUTOCAL (Front panel button or 24VDC pulse on external terminal)
4. AUTORANGE load scan activates simultaneously upon AUTOCAL startup

Controller sends low-level test excitation signal to transformer secondary circuit

Raw sampled amplitude of Ur and Ir is captured

MCU switches gain of internal analog front-end automatically to match measured U₂ & I₂

5. After successful range matching, sampling parameters are locked; yellow AUTOCAL LED illuminates continuously
6. Baseline resistance sampling completes (aprox. 10～15s). Calibration finishes and ranging parameters are saved.
7. The identified range parameters are applied for closed-loop temperature control in all subsequent heating cycles

⚠️ AUTORANGE only performs load scanning during AUTOCAL calibration. Dynamic range switching will NOT occur during normal heating operation.

AUTOCAL must be re-executed to refresh AUTORANGE load identification after replacing heat-sealing band, pulse transformer or modifying sealing strip length!

3. Engineering Benefits of AUTORANGE (Comparison with Old Version with Manual DIP Switches)

4. Prerequisites & Limitations of AUTORANGE (Critical Know-how to Avoid Field Failures)

✅ Supported Operating Conditions

1. Pulse transformer secondary voltage: Minimum 0.4VAC, maximum 80VAC
2. Steady-state secondary operating current ≥30A; AUTORANGE fails and triggers alarms if current <30A (UR/IR signal error)

Narrow sealing strips with operating current below 30A represent the most frequent field pitfall!

3. Unbroken secondary circuit; no open circuit or loose terminals on heat-sealing band
4. Number of CT winding turns strictly follows ROPEX specifications

(Multiple primary turns through CT are recommended for current <100A to boost sampling signal amplitude)

❌ Parameters AUTORANGE CANNOT automatically adjust; Manual verification required

1. Current transformer winding turns: AUTORANGE cannot detect CT turns; wrong turns lead to temperature reading deviation
2. Mains frequency: Although 47–63Hz auto-adaptive, this function is independent from AUTORANGE
3. Heat-sealing band material (A20 alloy etc.): Related to internal temperature characteristic curves, irrelevant to ranging
4. Main supply voltage (115/230/400VACACIONES): Determined by controller model; not processed by AUTORANGE
5. Typical Fault Phenomena Rooted in AUTORANGE and Analysis

Controller Alarm: UR signal error / IR signal error (Red ALARM LED flashing)

1. Transformer secondary voltage U₂＜0.4V or＞80VAC, exceeding AUTORANGE range limits
2. Secondary operating current＜30A, below minimum detection threshold
3. Broken heat-sealing band, loose terminals or open secondary circuit → No valid sampling signal during AUTORANGE scanning
4. Incorrect CT installation, wrong winding turns or damaged current transformer
5. AUTOCAL initiated while the heat-sealing band remains hot; variable load impedance disrupts scanning
6. Old hardware manufactured before 2005 (No AUTORANGE); operators mistakenly treat it as updated unit without setting DIP switches
7. AUTORANGE Performance Comparison with Successor Models
8. RES‑420: Enhanced AUTORANGE, secondary voltage range extended to 0.4～120VAC, identical current limits
9. RES‑5010: Fully digital sampling, retains automatic load identification plus fieldbus communication capability
10. Standard On-site Commissioning Procedure
11. Complete all wiring; ensure heat-sealing band fully cools to room temperature
12. Deactivate START heating signal
13. Power on controller and wait at least 10 artículos de segunda clase
14. Trigger AUTOCAL calibration (Front panel button or external terminal pulse)
15. Confirm yellow AUTOCAL LED lights steadily for 10~15s then extinguishes → AUTORANGE scanning + zero calibration fully completed
16. Run trial operation; verify stable temperature reading without alarms

Maintenance Rule: Re-run AUTOCAL to refresh AUTORANGE load parameters every time heat-sealing band, pulse transformer or sealing structure is modified!