Selection Guide for Phoenix Contact PC4001 Controller for 55KW Refrigeration Units
The Phoenix Contact PC4001 is a high-performance controller designed specifically for industrial refrigeration equipment, and it is fully capable of meeting the control requirements of 55KW refrigeration units. This guide is presented in four aspects: paramètres de base, caractéristiques fonctionnelles, key selection points, and application cases.
- Correspondance des paramètres de base
1.1 Basic Performance Parameters
| Paramètre | Spécification | Notes d'application |
| Tension d'entrée nominale | AC 220V/380V | Supports common industrial power supplies and is compatible with standard power for refrigeration units |
| Puissance de contrôle | Max.. 55KW | Fully covers the control requirements of 55KW refrigeration units |
| Interfaces de communication | RS485/Modbus RTU, Ethernet | Supports remote monitoring and data transmission for easy system integration |
| Température de fonctionnement | -10℃~+60℃ | Adapts to harsh industrial environments with high stability |
| Classe de protection | IP65 | Anti-poussière et étanche, suitable for installation in control cabinets |
1.2 Special Functions for Refrigeration Units
Compressor Control: Supports soft start and soft stop to avoid inrush current and protect the compressor
Multi-Mode Switching: Supports fixed-frequency / variable-frequency mode switching to adapt to different cooling demands
Fault Protection: Built-in overcurrent, surtension, and overload protection to ensure safe unit operation
Surveillance à distance: Supports remote status viewing and parameter modification via mobile APP and PC
- Points clés de sélection
2.1 Hardware Configuration Requirements
- Module d'alimentation: A dedicated switching power supply is required, input AC 220V, output DC 24V, to power the controller
- Module de communication: Choose RS485 or Ethernet according to on-site needs; Ethernet is recommended for faster transmission
- Sensor Interfaces: Reserved interfaces for temperature and pressure sensors to monitor unit operating status
- Sorties relais: Supports up to 8 relay outputs for controlling compressors, les fans, et autres équipements
2.2 Software Function Requirements
- Programming Environment: Supports PLCopen standard programming languages for custom control logic
- Enregistrement des données: Supports operating data storage and historical record query for equipment maintenance
- Alarm Function: Supports multi-level alarms with push notifications via SMS, e-mail, or APP
- Compatibilité: Compatible with mainstream refrigeration unit brands such as Bitzer, Copeland, Hanbell, etc..
- Cas de candidature & Remarques
3.1 Cas d'application typique
A 55KW refrigeration unit in a food processing plant is controlled by the Phoenix Contact PC4001, achieving the following functions:
- Soft start of the compressor, reducing starting current by 30% and extending service life
- Remote monitoring of unit status with real-time viewing of temperature, pression, et d'autres paramètres
- Automatic alarm function to send timely alerts to managers’ mobile devices in case of faults
- Data statistics and analysis to support equipment maintenance
3.2 Précautions de sélection
- Confirm Unit Model: Control logic varies slightly among different brands; select a matching controller
- Consider Expansion Needs: Choose a controller with expandable functions for future sensor or module additions
- After-Sales Support: Select suppliers with technical support and after-sales service to ensure stable operation
- Exigences de conformité: The controller must comply with industry standards such as CE, UL, etc..
The Phoenix Contact PC4001 controller is an ideal choice for 55KW refrigeration units. Its powerful hardware configuration and rich software functions meet all control demands of refrigeration units. Pendant la sélection, comprehensively consider the unit model, expansion requirements, and compliance standards to ensure an appropriate match.
D'abord, a critical correction:
Phoenix Contact PC 4001 (RFC 4001) is a general-purpose PLC controller, not a dedicated refrigeration control board. It must be used with digital and analog I/O modules to control a 55kW refrigeration unit.
Below is engineering-ready content: I/O point list + standard wiring diagram + control logic + programming essentials, based on a standard 55kW screw/piston water chiller with star-delta starting.
- Overall System Configuration (55kW Refrigeration Unit + PC4001)
1.1 Core Equipment
Contrôleur: Phoenix RFC 4001 (PC4001)
I/O Modules:
Entrée numérique (DEPUIS): IB IL 24 DEPUIS 16
Relay Digital Output (FAIRE): IB IL 24 FAIRE 16-R
Entrée analogique (IA, 4–20mA / PT100): IB IL AI 4/I + IB LE PT4
Actuators:
55kW compressor with star-delta starting (KM1 main contactor, KM2 star contactor, KM3 delta contactor)
2× condenser fans, 2× evaporator fans
Liquid supply solenoid valve, hot gas bypass valve
Protection & Sensing:
High-pressure switch, low-pressure switch, oil pressure differential switch, interrupteur de débit d'eau, phase sequence protector
Pressure sensors (haut / faible), temperature sensors (oil temperature, evaporation, condensation)
1.2 Applicable Unit Types
Water chiller / industrial air cooler / cold storage unit
Compresseur: 55kW 380V three-phase
Starting Method: Star-delta reduced-voltage starting (most common and cost-effective)
- I/O Point Assignment List (Directly Usable for Programming)
2.1 Entrées numériques (DEPUIS, 24À DC)
| Adresse | Signal Name | Signal Type | Remarques |
| %IX0.0 | High Pressure Protection Switch | Normalement fermé | Alarm when open |
| %IX0.1 | Low Pressure Protection Switch | Normalement fermé | Alarm when open |
| %IX0.2 | Oil Pressure Differential Switch | Normalement fermé | Alarm when open |
| %IX0.3 | Water Flow Switch | Normalement ouvert | Alarm for no water flow |
| %IX0.4 | Phase Sequence Protector | Normalement fermé | Alarm for phase loss / reverse phase |
| %IX0.5 | E-Stop Button | Normalement fermé | Shutdown when pressed |
| %IX0.6 | Local/Remote Switch | Normalement ouvert | Local = 1 |
| %IX0.7 | Unit Start Command | Normalement ouvert | Panel / télécommande |
| %IX1.0 | Unit Stop Command | Normalement ouvert | Panel / télécommande |
2.2 Entrées analogiques (IA)
| Adresse | Signal | Plage de mesure | But |
| %IW2.0 | Discharge High-Pressure Sensor | 4–20mA / 0–3.0MPa | Contrôle + Protection |
| %IW2.1 | Suction Low-Pressure Sensor | 4–20mA / 0–1.0MPa | Contrôle + Protection |
| %IW2.2 | Oil Temperature PT100 | -40–120℃ | Protection contre la surchauffe |
| %IW2.3 | Evaporation Temperature PT100 | -40–80℃ | Contrôle de la température |
| %IW2.4 | Condensing Temperature PT100 | -20–80℃ | Fan Control |
2.3 Sorties numériques relais (FAIRE, 250V AC Rated)
| Adresse | Output Name | Controlled Device |
| %QX0.0 | Main Contactor KM1 | Compressor Main Power |
| %QX0.1 | Star Contactor KM2 | Compressor Star Starting |
| %QX0.2 | Delta Contactor KM3 | Compressor Delta Running |
| %QX0.3 | Condenser Fan 1 | Ventilateur de refroidissement |
| %QX0.4 | Condenser Fan 2 | Ventilateur de refroidissement |
| %QX0.5 | Evaporator Fan 1 | Indoor Fan |
| %QX0.6 | Evaporator Fan 2 | Indoor Fan |
| %QX0.7 | Liquid Supply Solenoid Valve | Refrigerant Supply |
| %QX1.0 | Hot Gas Bypass Valve | Surge Prevention / Temp Control |
| %QX1.1 | Common Alarm Output | Audible and Visual Alarm |
- Schéma de câblage standard (Simplified Engineering Version, Directly Applicable)
3.1 Controller Power Supply
PC4001 Power: 24V DC ±20%
L+ → 24V+
M → 0V/GND
PE → Ground
3.2 Entrée numérique (DEPUIS) Câblage (NPN Common Cathode)
Uniform wiring for all switches/buttons:
One terminal of switch → 24V+
Other terminal of switch → PLC DI terminal (%IX0.0~%IX1.0)
Common terminal M → 0V
3.3 Entrée analogique (IA) Câblage
4–20mA Sensors:
Capteur + → AI channel +
Sensor – → AI channel –
Shield grounded at one end
PT100 Temperature Sensors:
3-wire connection to corresponding terminals of IB IL PT4
3.4 Sortie numérique (FAIRE) Câblage (Relay Contacts)
PLC DO terminal → Contactor Coil A1
Contactor Coil A2 → Neutral Line N
RC snubber / freewheeling diode connected in parallel across contactor coils
3.5 Key Points for 55kW Compressor Star-Delta Power Wiring
KM1: Main power input
KM2: Star point (disconnected after 5–8 seconds of starting)
KM3: Delta running
Interlock: KM2 and KM3 must NOT be energized simultaneously
Thermal relay connected in series in the main circuit for overload tripping
- Fully Automatic Control Logic (Standard Refrigeration Unit Sequence)
4.1 Start Permissive Conditions (All Must Be Satisfied)
- No high-pressure / low-pressure / oil pressure / débit d'eau / séquence de phases / E-stop alarms
- Local/remote switch set to allow operation
- Start command issued
4.2 Start Sequence
- First start evaporator fans + condenser fans
- Delay 3 seconds → open liquid supply solenoid valve
- Delay 2 seconds → compressor star-delta start
KM1 + KM2 energized (star connection)
Delay 6 seconds → KM2 de-energized, KM3 energized (connexion en triangle)
- Enter automatic temperature control
4.3 Automatic Temperature / Pressure Control
Evaporation temperature ≥ setpoint + deadband → compressor runs
Evaporation temperature ≤ setpoint − deadband → compressor stops
Excessively high condensing temperature → start condenser fans sequentially
Excessively high discharge pressure → start fans first; alarm and shutdown if pressure remains high
4.4 Logique de protection (Immediate Shutdown)
Any of the following triggers an immediate:
Compressor stop + solenoid valve close + sortie d'alarme
Trigger Conditions:
High-pressure switch open
Low-pressure switch open
Oil pressure differential switch open
Water flow switch open
Phase sequence abnormality
E-stop pressed
Discharge pressure > 2.8MPa
Oil temperature > 90℃
4.5 Shutdown Sequence
- First stop the compressor
- Delay 15 seconds → close liquid supply valve
- Delay 1 minute → stop fans (residual heat purging)
- PC4001 Programming Guide (PC Worx)
5.1 Software & Langue
Software: PC Worx (Phoenix Contact dedicated)
Langue: Diagramme en échelle (LD) / Schéma des blocs fonctionnels (FBD) (most common in refrigeration industry)
5.2 Core Program Structure
- Initialization Block: Reset alarms, set default parameters
- Alarm Judgment Block: Central processing of all protection signals
- Start Permissive Logic Block
- Star-Delta Timing Block (TON timer)
- Automatic Temperature Control PID Block
- Fan Interlock Block
- Output Execution Block
5.3 Key Program Examples (Ladder Logic)
(1) Start Permissive
Start_Permissive := No_Alarm AND Start_Command AND NOT Stop_Command AND Local_Enable;
(2) Star-Delta Timing
TON1 Star Timer: 6s
Logic:
Start_Permissive → KM1, KM2 Output
TON1 Time Up → KM2 Reset, KM3 Set
Hardware + software interlock for KM2, KM3
(3) Alarm Interlock
IF High_Pressure_Alarm OR Low_Pressure_Alarm OR Oil_Pressure_Alarm OR E-Stop THEN
Compressor_Stop;
Solenoid_Valve_Close;
Alarm_Output := 1;
END_IF;
5.4 Recommended Parameters (General for 55kW Units)
Star-delta delay: 5.0–6.5s
Evaporation temperature setpoint: 5–7℃ (water chiller) / -10–-25℃ (chambre froide)
High-pressure alarm threshold: 2.8 MPa
Low-pressure alarm threshold: 0.15 MPa
Oil temperature protection: 90℃
Condensing temperature for fan start: 38℃
- Étapes de mise en service
- First test all DI/AI signals individually for correct operation
- Jog each DO output individually to test contactors/valves
- Simulate protection signals (short/open) to verify shutdown logic
- No-load star-delta test run to confirm no phase-to-phase short circuit
- Load operation, observe pressure and temperature curves
- Fine-tune PID parameters to avoid frequent starting/stopping
- Engineering Safety Notes
- 55kW is high power: Power cables must be ≥ 16mm² with reliable grounding
- Separate PLC low-voltage wiring from 380V high-voltage wiring by ≥ 20cm
- Contactors must have electrical + software interlock to prevent damage
- All sensor shields grounded at one end to avoid interference
- Always disconnect power before wiring; hot-plugging I/O modules is prohibited
Please let me know:
1) Whether it is a water chiller or cold storage unit
2) Whether it uses star-delta, démarreur progressif, or VFD
3) Whether Modbus remote monitoring is required
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