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ctrl32
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Function block diagram (FBD)

FBD: composite blocks, axes and drive control

Machine control in ctrl32 is assembled from blocks in an FBD diagram — the logic is data in the pack, not code in the firmware. Besides the fixed block library (TON, PID, … — see widgets.md) there are:

Composite block (an FB built from blocks)

A composite is a POU with an interface (input/output ports) and its own internal FBD network. In a diagram it is used like an ordinary block; a double-click opens it and shows how it is put together. At compile time it is flattened into primitives — the panel executes a flat list, with no recursion and no extra interpreter.

  • Creating one: right-click on Application → Add Composite FB; the ports are edited with the Ports… button in the diagram (max 4 inputs, 2 outputs). Changing the interface bumps the block version.
  • Supplied blocks (for example DRIVE_i550 from libraries/) are read-only — you can look inside, but not change it. Save as own creates an editable copy in the project.
  • In YAML: the composites: section; inside the body $PORT marks an interface port and ~wire an internal wire (every use of a composite gets its own wires — instances do not share state).
  • Limits: nesting depth 8, recursion forbidden, at most 64 blocks AFTER flattening — all of it enforced by the compiler, not the panel.

Axis (AXIS) and drives

An axis is a drive controlled by motion blocks. It is added by right-clicking its bus node in the device tree (CANopen master → CiA402, SPI → POWERSTEP01 or TMC5160 — the node decides the backend) and carries the backend and its parameters:

Backend Bus Status
CiA402 (Lenze i550) CANopen tested on the bench
POWERSTEP01 SPI interface ready, driver ships with the hardware
TMC5160 / TMC5130 SPI driver written from the datasheet, mock-tested — verify on the bench

Blocks bound to an axis (they have an axis selector in the top bar of the diagram):

  • MC_POWER — switch the axis on (Status = axis in operation)
  • MC_MOVEVELOCITY — velocity; it also accepts a change of the setpoint while running
  • MC_STOP — controlled stop along the decel ramp
  • MC_RESET, MC_READACTVEL, MC_READSTATUS
  • positioning MC_MOVEABS/MOVEREL/HOME/READACTPOS (for the SPI stepper backends POWERSTEP01 / TMC5160)
  • CO_CIA402 — the core of the state machine (a building block for composites)
  • CO_SDOWRITE — writes a parameter at startup (it is translated into commissioning; an SDO is never executed inside the cycle)
  • CO_RAMPTIME — ACC/DEC ramp times in seconds for the commanded speed; they are written to the drive only while the axis is stopped

The supplied DRIVE_i550 block

              ┌────────────────┐
  command ────┤ Enable Running ├──── running
  setpoint ───┤ Speed  ActualS.├──── speed
  direction ──┤ Reverse        │
              └───────┬────────┘
                      axis1 (CANopen node …)

Inside: MC_POWER + MC_MOVEVELOCITY + MC_READACTVEL. STOP = dropping Enable → the drive coasts down along its own decel ramp and disables itself. Read the diagnostics (current, torque, DC link, frequency …) with CANopen data tags and gain scaling (for example ‰ → A); no blocks are needed for that.

Verified i550 objects: the actual output frequency is 0x2DDD (0.1 Hz); 0x2D87 is the ramped setpoint (at standstill it holds the setpoint).

Safety

The motor only starts from a deliberate operator command (a button on the display / in WEBview). Stopping over CANopen is not a safety function — the drive's STO terminals and the limit switches must be hard-wired.

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