A PCO5 is useless without a user interface. The c.STER software is used to program the graphic displays (pGD1, pGD2) that connect to the PCO5.
While you write logic in c.pCO Suite, you design screens in c.STER. The "top" feature here is the dynamic data binding – you draw a chiller schematic on the screen, link it directly to a variable in the PCO5 (e.g., Evaporator_Pressure), and c.STER converts it into the pGD language.
Pro Tip: The integration between c.pCO Suite and c.STER is seamless. You can assign string tables and alarm messages in c.pCO that automatically populate in c.STER.
In the world of HVAC/R and industrial refrigeration control, few names carry as much weight as Carel. The Carel PCO5 series represents a benchmark for programmable controllers, offering robustness, flexibility, and high performance for complex applications like chiller units, rooftop packages, and refrigeration racks.
However, the hardware is only half the story. The true power of the PCO5 is unlocked through its dedicated programming environment. When searching for the Carel PCO5 programming software top tools, engineers and technicians are looking for more than just a code editor; they seek a complete ecosystem for logic design, interface creation, debugging, and remote management.
This article provides a comprehensive guide to the top-tier software used to program the Carel PCO5, focusing on c.pCO Standard, c.pCO Suite, c.STER, and supporting tools like PlantVisor PRO.
To begin programming, you need the correct software version. As of 2025, the primary tool is pCOSoft +3 or the newer c.Suite (Carel’s evolution towards IoT programming). However, for legacy and stable pCO5 projects, pCOSoft remains the standard.
One of the most critical software functions is managing the EEPROM (non-volatile memory). The software allows you to:
Having the software is only half the battle. Here are three tips for effective programming:
It sounds like you’re looking for a piece of Carel PCO5 programming software — likely the top part of a program (e.g., a main routine, a configuration header, or a state machine start).
Since Carel PCO controllers are typically programmed in CAREL μC (microC) or structured text (similar to IEC 61131-3), below is a commented example of a top-level program section for a PCO5 controller managing a HVAC/refrigeration unit.
This example includes:
// ********************************************************************** // Program: MAIN_TOP // Controller: Carel PCO5 // Language: CAREL μC (C-like) // Description: Top-level program section for HVAC/Refrigeration unit control // **********************************************************************// ---------------------------------------------------------------------- // 1. INPUT DEFINITIONS (Physical & Virtual) // ---------------------------------------------------------------------- // Analog Inputs (from PCO5 expansion or onboard) AI_AI1 : // Pressure transducer (4-20 mA) -> Bar AI_AI2 : // Temperature probe NTC (Evaporator) AI_AI3 : // Suction temperature
// Digital Inputs DI_ON_OFF : // Unit enable (ON=1) DI_SAFETY_CHAIN : // High pressure / low pressure safety (OK=1) DI_DOOR_OPEN : // Refrigerated cabinet door status
// ---------------------------------------------------------------------- // 2. OUTPUT DEFINITIONS // ---------------------------------------------------------------------- DO_COMPRESSOR : // Compressor contactor DO_FAN : // Condenser fan DO_ALARM_BUZZER : // Alarm output
// ---------------------------------------------------------------------- // 3. INTERNAL VARIABLES // ---------------------------------------------------------------------- VAR running : bool; // Unit running flag alarm_active : bool; // Global alarm status compressor_delay : int; // Anti-short cycle delay (seconds) temp_setpoint : real; // Temperature setpoint (°C) temp_deadband : real; // Deadband value state : int; // 0=Off, 1=Pre-run, 2=Run, 3=Fault END_VAR
// ---------------------------------------------------------------------- // 4. INITIALIZATION (Executes once at power-up) // ---------------------------------------------------------------------- INIT: running = FALSE; alarm_active = FALSE; compressor_delay = 0; temp_setpoint = 2.0; // °C for refrigeration temp_deadband = 1.0; state = 0;
// Force outputs safe state DO_COMPRESSOR = 0; DO_FAN = 0; DO_ALARM_BUZZER = 0;END_INIT
// ---------------------------------------------------------------------- // 5. TOP-LEVEL CYCLIC LOGIC (Main state machine start) // ---------------------------------------------------------------------- BEGIN_CYCLE:
// Read inputs (refresh in PCO5) // (Carel μC reads I/O automatically before each cycle) // 5.1 SAFETY OVERRIDE IF (DI_SAFETY_CHAIN == 0) THEN state = 3; // Fault state alarm_active = TRUE; END_IF // 5.2 STATE MACHINE (top-level control) CASE state OF 0: // Unit OFF DO_COMPRESSOR = 0; DO_FAN = 0; IF (DI_ON_OFF == 1 AND DI_SAFETY_CHAIN == 1) THEN state = 1; // Move to Pre-run compressor_delay = 60; // 60 sec anti-short cycle END_IF 1: // Pre-run (delay before start) IF (compressor_delay <= 0) THEN state = 2; ELSE compressor_delay = compressor_delay - 1; // Decrement per second // (Assume cycle time = 1 sec for simplicity) END_IF 2: // Running DO_COMPRESSOR = 1; DO_FAN = 1; // Basic temperature control (example) // IF evaporator temp > setpoint+deadband -> stay on // ELSE IF temp < setpoint -> stop (back to state 0) IF (AI_AI2 < (temp_setpoint - temp_deadband)) THEN DO_COMPRESSOR = 0; DO_FAN = 0; state = 0; END_IF // Safety check IF (DI_SAFETY_CHAIN == 0 OR DI_ON_OFF == 0) THEN state = 3; END_IF 3: // Fault/Alarm state DO_COMPRESSOR = 0; DO_FAN = 0; DO_ALARM_BUZZER = 1; // Activate alarm output // Manual reset required (toggle ON/OFF to reset) IF (DI_ON_OFF == 0) THEN alarm_active = FALSE; state = 0; END_IF END_CASEEND_CYCLE
// ---------------------------------------------------------------------- // 6. END OF TOP-LEVEL PROGRAM // ----------------------------------------------------------------------
Notes for actual use on PCO5:
If you meant the top part of a specific Carel application (like a supermarket rack controller or AHU), please clarify, and I can adjust the example accordingly.
To program or update a CAREL pCO5 controller, you'll likely use 1tool, STone, or c.suite, depending on your specific hardware model and project needs. Top Software Options for pCO5
1tool: The primary development environment for the pCO series. It’s known for a visual "function block" approach, allowing you to drag and drop elements like logic gates or HVAC-specific modules.
STone: CAREL’s newest platform, focused on Structured Text (ST) programming. It offers modern security features like secure boot and is designed for the latest generation of pCO5+ and HS (High Speed) models.
c.suite: A modular development suite often used for the c.pCO family. It supports multiple IEC 61131-3 languages (Ladder, FBD, ST) and is built for team-based collaborative programming. Service Tools for Commissioning
If you aren't writing code from scratch but need to maintain a unit, these tools are essential:
pCOManager: Used for commissionging and managing binary files—perfect for loading pre-written software onto the controller.
APPLICA & CONTROLLA: Mobile apps for field technicians to adjust parameters via Bluetooth, NFC, or Wi-Fi without needing a PC.
USB Port Utility: Most pCO5 models have a built-in USB port. You can often update the entire PLC program or firmware simply by plugging in a formatted thumb drive. Quick Tips for Programming
Compatibility: The pCO5 is pin-to-pin compatible with older pCO3 units, meaning you can often migrate old projects using a BIOS emulation mode.
Training: Unlike generic PLC software, CAREL often requires attending a specific training course before you can purchase or fully unlock 1tool. carel pco5 programming software top
Are you looking to develop a custom algorithm from scratch, or do you just need to update the firmware on an existing unit? Programming Tools - CAREL
The primary programming software for the CAREL pCO5 controller is 1tool. Newer versions of the controller, specifically the pCO5+, can also be programmed using the more modern STone development environment. Core Programming Tools
1tool: The legacy development tool for the CAREL programmable platform. It features five integrated environments for designing, testing, debugging, and commissioning HVAC/R control strategies.
STone: The latest environment designed for efficiency and security. It uses Structured Text (ST) language according to IEC 61131-3 standards and includes advanced features like secure boot and digital signatures for pCO5+ models.
c.suite: While primarily developed for the newer c.pCO family, it is the upgraded successor to 1tool and focuses on modular development for complex HVAC/R systems. Software Access & Activation
Licenses and software modules must typically be activated through the CAREL Software Activation Portal. Connection & Maintenance Tools pCO5+ - CAREL
The Carel PCO5 Programming Software Top is not just a tool; it is a gateway to absolute control over your HVAC/R assets. Whether you are retrofitting an old supermarket rack or designing a new pharmaceutical chiller, mastering this software suite allows you to push the pCO5 hardware to its limits.
From PID autotuning to pLAN synchronization, the TOP environment offers the granularity that ladder logic cannot match. While the industry evolves toward cloud-native interfaces, the deterministic, real-time power of a well-written TOP program on a pCO5 remains the gold standard for mission-critical climate control.
Ready to take the plunge? Download pCOSoft+, grab your programming dongle, and connect to a pCO5. The first time you see your custom algorithm keep a temperature within ±0.1°C, you will understand why the Carel PCO5 Programming Software Top is, well, on top.
Have a specific question about TOP syntax or pCO5 networking? Leave a comment below or contact an authorized Carel support center. For more deep dives into industrial automation, subscribe to our newsletter.
Here’s a solid, practical piece of content for Carel PCO5 programming software — structured as a guide or LinkedIn/tech post, depending on your need. A PCO5 is useless without a user interface
This defines the scan cycle. The pCO5 runs in cycles (e.g., 100ms). You assign code blocks to different cycles (Fast, Medium, Slow) to optimize CPU load.