The PP C322 BE is a high-performance, general-purpose programmable controller developed by ABB Industrie AG for its PSR system. PSR, standing for "Programmierbarer Schneller Regler" (Programmable Fast Controller), indicates the system is specifically designed for industrial applications requiring high-speed, high-precision control tasks. The PP C322 BE can handle complex, dynamic processes, such as precise control of motor torque, speed, and flux in scenarios like steel, mining, marine propulsion, and large fan/pump applications.
2. Core Architecture & Operating Principle
The core operating principle of the PP C322 BE is based on a Function Block Programming Language. This is a graphical programming paradigm that encapsulates complex control algorithms, logical operations, and mathematical computations into standardized, reusable functional units called "Function Blocks."
2.1 Function Blocks: The Building Blocks of Control
Each function block is an independent software module performing a complete function, characterized by:
Graphical Symbol: Represented as a rectangle in the programming interface, with inputs on the left and outputs on the right, facilitating intuitive understanding and logic construction.
Standardized Interface: Each input and output has a strictly defined data type (e.g., Percent, Boolean, Integer, BCD), ensuring data consistency in connections.
Configurability: Most blocks have parameter pins, allowing users to adjust behavior (e.g., setting a PI controller's proportional gain, integral time) without altering core logic.
Expandability: Many blocks (e.g., Adder ADD, AND gate) have expandable inputs (up to 32), achievable by adding pins graphically, optimizing program structure and execution efficiency without cascading multiple blocks.
2.2 Precision in Data Type Design
The PP C322 BE supports a rich set of data types to meet diverse control task requirements, reflecting its precise design:
Boolean (B): Represents True/False (1B/0B), used for logic control.
Bitset (BS): A 16-bit word where each bit can be manipulated independently, often used for packing multiple Boolean signals or representing device status words.
Percent (%): The primary format for analog processing. It's a 16-bit fixed-point number ranging from -199.9939% to +199.9939%. This representation is ideal for control systems, directly corresponding to per-unit values or full-scale percentages. 32-bit double precision percent is also supported for higher dynamic range and accuracy.
Integer (I) & Long Integer (LI): 16-bit and 32-bit signed integers for counting and discrete value handling.
Factor (K), Millisecond (MS), Second (S): Dedicated formats for time constants, scaling factors, and time delays, simplifying parameterization.
BCD: Used for data exchange with external devices like digital displays or thumbwheel switches.
Word (H): A generic 16-bit data container.
Data Type Compatibility Matrix ensures only compatible types can be interconnected, preventing data type errors at the language level; otherwise, explicit conversion using TRAN or TRANW function blocks is required.
2.3 Execution Mechanism & Real-Time Performance
The controller program consists of a sequence of function blocks executed in order. The PP C322 BE supports multi-tasking, including interrupt tasks and a background task.
Interrupt Tasks: Used for executing time-critical fast control loops, triggered accurately by hardware timers (e.g., Timer 0 at 2000 microseconds mentioned in the doc). This is crucial for high-frequency responses like current and speed loops.
Background Task: Handles non-real-time operations like communication, parameter management, and slow logic.
3. Core Functional Categories & In-Depth Principle Analysis
Key categories are explained below:
A. Basic Analog & Arithmetic Functions
These form the foundation of control algorithms.
Arithmetic Operations: ADD (Addition/Subtraction), MULT (Multiplication), DIV (Division), SQRT (Square Root) perform basic math. They use fixed-point arithmetic internally and handle overflow properly (output limited to max/min values).
Function Generation: FCTL (Linear Function Generator) approximates arbitrary curves via linear interpolation between user-defined breakpoints (X,Y). FCTP (Polynomial Function Generator) handles more complex non-linear relationships, computing polynomial values using Horner's method for efficiency.
Trigonometric Functions: SIN, COS, ASIN, ACOS directly process angles (in radians, mapped to percent format). These are essential for coordinate transformations and phase calculations. The doc precisely specifies their input/output ranges and overflow conditions, e.g., ACOS input must be > -41.6092% to avoid results exceeding the percent range.
B. Basic Logic & Sequential Functions
Implement digital logic and sequence control.
Logic Gates: AND, OR, EXOR support Boolean and Bitset formats for combinatorial logic.
Flip-Flops: RSFF (RS Flip-Flop, reset-dominant), TOGFF (T Flip-Flop) for state storage.
Timers & Counters:
MS, MS& (Monostable Multivibrators): Generate fixed-width pulses. MS is non-retriggerable, MS& interrupts output if input goes low. Their timing accuracy relates to the controller cycle time, as documented.
OND, OFD, OOD (On-Delay, Off-Delay, On/Off-Delay): Used for signal filtering and timing coordination.
CNT, PBCNT (Counters): Implement event counting and comparison.
C. Highly Integrated & Control Algorithms
This embodies the core power of the PP C322 BE.
PI Controllers (PI-R0, PI-R1):
Principle: The classic control algorithm. The Proportional (P) part provides fast response, the Integral (I) part eliminates steady-state error. These are discrete-time, digital implementations. The integration formula is: o(k) = o(k-1) + [i(k) + i(k-1)]/2 * (T0/TN), using the trapezoidal (Tustin) method, more accurate than simple rectangular integration.
Features: Both PI-R0 and PI-R1 support setpoint/feedback comparison, error signal input, output limiting, integrator initial condition setting, and anti-windup. PI-R0 additionally provides independent integrator limits (UPL-I, LOL-I), offering a more flexible anti-windup strategy.
Coordinate Transformations (RSTDQ, DQRST, DQPOL):
Principle: Core to vector drive control. RSTDQ transforms three-phase AC quantities from the stationary reference frame (R, S, T) to DC quantities in a two-phase rotating reference frame (d, q). This transformation (comprising Clarke and Park transforms) converts time-varying AC parameters (e.g., current, voltage) into DC parameters (torque component, flux component) ideal for control.
Application: DQRST performs the inverse transformation, converting d, q DC quantities back to three-phase AC quantities for generating PWM waveforms. DQPOL converts from Cartesian coordinates (d, q) to polar coordinates (magnitude |A|, angle PHI), often used for calculating flux magnitude, etc.
These blocks greatly simplify the implementation of Field-Oriented Control (FOC) algorithms in AC drives.
Integrators (INT, INT-I):
INT has an integration time constant based on a fixed hardware time base (1ms or 1s), suitable for integration strictly related to physical time.
INT-I has an integration coefficient related to the interrupt task cycle time (T0). Its output is o(k) = o(k-1) + (T0/TI) * [i(k) + i(k-1)]/2. This synchronizes integration behavior with the program execution frequency, making it more common and precise in digital control systems.
Digital Filters (AVG, AVG-M, G2(Z)):
AVG is a moving average filter, suppressing specific frequency noise by averaging the last N samples.
G2(Z) is a general-purpose second-order difference equation implementation, configurable as various filters (e.g., low-pass, high-pass, band-pass) or even an oscillator. Its transfer function is G(z) = (A0 + A1*z⁻¹ + A2*z⁻²) / (1 + B1*z⁻¹ + B2*z⁻²). By setting coefficients A0-A2 and B1-B2, nearly any linear time-invariant discrete system can be realized.
D. Data Management & Communication
Data Conversion: %-BCD, BCD-%, BIBS, BSBI, MERGE, SPLIT handle conversions between different data formats and bit-widths, acting as a bridge between the controller and the external world (e.g., displays, encoders).
Bus Communication: RDLA, WRLA are used for reading/writing data in the long address space of the B448 bus (an ABB proprietary industrial bus). SLAVE-I is used during system initialization to configure the address, mailbox size, and parameters of other slave devices on the bus, forming the foundation for multi-device system coordination.
E. Diagnostics & Advanced Functions
Transient Recorder (TREC): An extremely powerful diagnostic tool. It can sample multiple signals continuously at high frequency and, upon a trigger condition (e.g., a fault signal), record data from before and after the trigger point. This data can be output periodically for connection to an oscilloscope or data logger, which is vital for analyzing system dynamic response and troubleshooting transient faults.
Signal Inspection & Parameter Modification (INSP): This function block allows authorized personnel (via KEY password protection) to online read and modify the values of any internal signals within the controller, including parameters. Used with Service Units (e.g., SD A338), it forms a powerful HMI and debugging tool.
Time Supervision (TSUP-US, TSUP-MS) & Event Recording (EVENT): Provide system operation monitoring and first-out fault annunciation compliant with DIN 19235, clearly indicating the sequence of fault occurrences.
4. Development & Configuration
Programming the PP C322 BE requires the use of ABB's PTS-Tools (Programming and Test System Tools). Engineers use a graphical interface on a PC to drag-and-drop required function blocks into a program, connect their inputs and outputs, and set parameters. The toolchain then compiles the graphical program into code executable by the controller, which is downloaded to the target device (PP C322 BE) via a loader.
The PP C322 BE must match the function block library version (e.g., C_R1_V20). Newer function blocks (e.g., ACOS, ASIN, BRREL) are only available in higher library versions, ensuring upward compatibility and continuous functional expansion.
