GE DC Drives (BCH series) upgrade and replacement of old DC drives

Expansion slots: 2 or 4 PCI slots that can accommodate communication cards such as Profibus, Profinet, Reflective Memory, CANbus, Modbus, EGD, etc

Programming environment: Complies with IEC 61131-3 standard, supports Function Block Diagram (FBD), Ladder Diagram (LD), Structured Text (ST)

Engineering significance: When the controller fails, it can be directly replaced with an industrial PC of the same model, and the application program can be reinstalled to restore it without waiting for the original factory's dedicated spare parts.

3.2 PIBe - Bridge Connecting Controller and Power Section

PIBe (Power Interface Board) is a critical interface board that connects PECe with on-site power devices such as thyristors, transformers, encoders, etc. Provide:

24 copper cables or 32 optical fibers output to thyristor trigger circuit (capable of withstanding 60V, 10A)

8-channel digital input (such as emergency stop, closing feedback)

4-channel digital output (such as contactor control)

8 analog inputs (± 10V, 4-20mA, used for current/voltage feedback)

4-channel analog output (for external instruments or auxiliary adjustment)

2-channel current transformer input (directly connected to Hall effect sensor or CT)

1-channel encoder input (for speed feedback)

Advantages of fiber optic isolation: For high voltage and strong interference scenarios (such as large rolling mills), using fiber optic triggered thyristors can completely solve the problems of common mode voltage and ground current, greatly improving reliability.

3.3 On site I/O and EtherCAT Technology

The upgrade plan supports modular on-site I/O (such as GE RSTi series), connected to PECe through EtherCAT bus.

EtherCAT technology features:

Real time transmission, with a cycle time as low as 125 μ s

High synchronization accuracy (<1 μ s jitter)

Supports a large number of binary/analog channels, suitable for complex logic interlocking (such as crane brake, limit switch, temperature monitoring)

Practical application: In the control of the coiler, the tension meter signal, speed encoder, limit switch, cooling fan status, etc. can all be connected to PECe through EtherCAT I/O to avoid long-distance analog signal attenuation.

3.4 Human Machine Interface (HMI)

Replace the original pointer instrument, selector switch, and neon light. Configure a local touch screen that typically displays:

Main screen: Armature voltage, current, speed, excitation current, operating status, alarm overview

Alarm history: Record the last 100 faults (such as overcurrent, demagnetization, overspeed, thyristor trigger failure)

Parameter adjustment: PI parameters, acceleration and deceleration time, current limiting, etc. can be fine tuned online

Benefits: Reduce control cabinet openings, simplify operations, and provide intuitive fault location.

Software Platform: P80i Toolbox

4.1 Overview of P80i

P80i is a unified software suite for GE Power Conversion, covering the entire drive lifecycle: configuration, programming, debugging, monitoring, and fault diagnosis.

Operating environment: Windows (7/10/11), connected to PECe controller via Ethernet.

Compliant with IEC 61131-3: Supports Function Block Diagram (FBD), Ladder Diagram (LD), Sequential Function Diagram (SFC), and Structured Text (ST). This allows engineers familiar with PLC programming to quickly get started without the need to learn specialized driver parameter languages.

4.2 Main functions and advantages

Function Description

Real time monitoring of all variables (current, speed, trigger angle, temperature) through online monitoring, with graphical trend curves

Offline simulation simulates drive behavior on a PC without real hardware, verifies control logic, and shortens on-site debugging time

Modular programming can reuse functional block libraries (such as current loop, speed loop, tension control) to enhance standardization levels

Version control engineering projects can be saved as text/binary files for easy backup and comparison of differences

Multi user support allows multiple people to connect to the same controller simultaneously and monitor different tasks separately

Typical Debugging Scenario - Magnetic Field Closed Loop Test (PERTU):

When the motor is not closed or the load is not connected on site, the excitation circuit can be tested separately through P80i - set the excitation current setting, observe the actual current feedback, adjust the PI parameters, and confirm that the thyristor triggers normally. This greatly reduces the risk time during motor debugging.

4.3 Alarm and Diagnostic Examples

The P80i is equipped with rich diagnostic functions, and common alarms include:

Firing Fail ": Loss of thyristor trigger pulse (check fiber or PIBe output channel)

Overcurrent ": Current feedback exceeds the limit (check CT signal or current loop parameters)

Field Loss: Low excitation current (check excitation bridge or motor field winding)

Encoder Fault: Speed encoder signal loss (check wiring and encoder power supply)

All alarms are time stamped and can be exported for analysis.

Engineering implementation steps: from old drives to new systems

The following is a typical process for upgrading a 15-year-old DC speed regulator (such as GE DV300, DC2000, or third-party brands) to a PECe+PIBe solution.