The specified finite state automaton (FSA) defines the behavior of the LAU as seen by the LAC. FSA state transitions are based on internal device events (e.g., occurrence of device errors, local inputs) or on the reception of FSA commands from the LAC. The error-free device may be in the idle state, configuration state, interrupted state, or command processor active state. In the latter, either directly received or batched commands are executed. In direct execution mode, the LAC sends single operation commands to the LAU. The LAU starts executing the command immediately after receiving the entire command and generates the command result. In batch mode, received operation commands are stored in command buffers. This allows the LAC to pre-program work plans within the LAU.

Two classes of operation commands are defined: process commands and system commands. Process commands directly trigger specific LAU behaviors, such as dosing a certain volume or shaking at a given frequency. System commands influence the type of command processing and are mainly used in batch mode. The general LAU control objects include the control word, the status word, the operation command result, and the system command parameter record (e.g., for loops). Additionally, specific objects for batch mode and direct execution mode are specified. The profile allows for the transmission of command structures via PDOs (process data objects) in a segmented manner, although this is not recommended.

CiA 434-2 specifies commands and parameters relevant for controlling dilutors, dispensers, and pump units. A dilutor aspirates a specified liquid volume into a syringe in the first step and dispenses this liquid in the second step. Among other functions (e.g., dispensing, serial dispensing, diluting, or generating a continuous flow), a dilutor unit may control drives (e.g., DC motors, stepper motors), various types of valves, or different types of syringes. A dosing pump relies on a variable-capacity vessel, such as a syringe, to aspirate and deliver precisely controlled volumes of liquids. The specified process commands distinguish between general commands and function-block-specific commands, such as those for dosing, valves, flow tables, and pressure tables. Additionally, it specifies how the supported function blocks are represented and how field values given in increments are converted to SI-unit-related process values. The values with appropriate SI units (coded as specified in CiA 890, formerly CiA 303-2) for current flow, accumulated volume, and current pressure, along with the remaining processing time, are detailed. At the end of this specification part, the detailed parameter sets for each function block are specified.