Settings

The Cassandra firmware is highly configurable through the settings.json file, typically located in the config/ directory. These settings control various aspects of the machine’s operation, including heating logic, press control, and Modbus communication parameters.

The configuration is divided into three main sections: General Settings, Device Configuration (Master/Slaves), and Partitions.

General Settings

These settings are grouped by their functional area. You can modify these values to tune the machine’s behavior without recompiling the firmware.

Heating

Parameters controlling the thermal management system.

Setting Name	Type	Key	Description
Always Warmup	bool	ALWAYS_WARMUP	If enabled, the system will always execute a warmup phase before starting a profile.
Always Stop PIDs	bool	ALWAYS_STOP_PIDS_ON_PROFILE_FINISHED	Automatically turn off all PID controllers when a heating profile completes.
Sequential Heating Exclusive	bool	SEQUENTIAL_HEATING_EXCLUSIVE	Enforces sequential startup of heaters to reduce peak power consumption.
Always Use Sequential	bool	ALWAYS_USE_SEQUENTIAL_HEATING	Forces the use of the sequential heating strategy for all heating operations.
PID Lag Compensation	bool	PID_LAG_COMPENSATION	Enables compensation logic for thermal lag in the PID control loop.
Max Temperature	long	MAX_TEMPERATURE	The maximum allowable temperature setpoint (e.g., 280°C). Safety limit.
Min Temperature	long	MIN_TEMPERATURE	The minimum allowable temperature setpoint (e.g., 10°C).
SP Deadband	long	SP_DEADBAND	The deadband range for the setpoint to prevent oscillation around the target temperature.

Press

Configuration for the press subsystem, including load cells and solenoids.

Setting Name	Type	Key	Description
Loadcell Slave ID 0	long	LOADCELL_SLAVE_ID_0	Modbus Slave ID for the first load cell amplifier. Master: 20, Slave: 21
Loadcell Slave ID 1	long	LOADCELL_SLAVE_ID_1	Modbus Slave ID for the second load cell amplifier. Master: 21, Slave: 20
Solenoid 0 Modbus Addr	long	SOLENOID_0_MB_ADDR	Modbus address for the first solenoid valve control.
Solenoid 1 Modbus Addr	long	SOLENOID_1_MB_ADDR	Modbus address for the second solenoid valve control.

Modbus RTU

Low-level communication settings for the RS485 bus.

Setting Name	Type	Key	Description
Operation Timeout	long	OPERATION_TIMEOUT	Timeout in milliseconds for Modbus operations.
Omron Read Interval	long	OMRON_E5_READ_BLOCK_INTERVAL	Time interval in milliseconds between block reads from Omron E5 controllers.

Device Configuration

This section defines the Modbus network topology.

Master

• Master Name: Defined as "plc". This represents the main Cassandra controller.

Slaves

A list of defined slave devices on the network.

• cassandra-1

Partitions

Partitions allow you to group individual controllers into logical units (e.g., “Left Side”, “Right Side”). This is useful for organizing the UI and managing multi-zone heating.

Cassandra Left

A partition containing controllers for the left side of the machine.

• Carina (Slave ID: 10)
• Castor (Slave ID: 11)

Cassandra Right

A partition containing controllers for the right side of the machine.

• Coma B (Slave ID: 12)
• Corvus (Slave ID: 13)
• Start Slave ID: 14 (Used for auto-generating additional controller entries)
• Num Controllers: 4

Configuration File Structure

For reference, the settings.json file follows this structure:

{
  "master": "plc",
  "slaves": ["cassandra-1"],
  "partitions": [ ... ],
  "settings": [
    {
      "enabled": true,
      "name": "ALWAYS_WARMUP",
      "group": "heating",
      "type": "bool",
      "value": true
    },
    ...
  ]
}