Namespaces
namespace	MeasurementTrigger
	Measurement-trigger bitmask — register 4200 (controllers only).

namespace	modbus

namespace	reg

Classes
class	Driver
	Main BASIS-2 driver. More...

struct	DriverResult
	Lightweight result wrapper. Aborts on `value()` if `!ok()`. More...

struct	DriverResult< void >

struct	InstantaneousData
	Decoded snapshot of registers 2100..2109 (one Modbus burst). More...

struct	InstrumentIdentity
	Static identification of an instrument (read once at init). More...

struct	InstrumentStatus
	Carries the global instrument health derived from `InstantaneousData`. More...

struct	MeasurementData
	Decoded measurement-window result (registers 4201..4215). More...

class	UartInterface
	CRTP base for the BASIS-2 serial transport. More...

Enumerations
enum class	DriverError : uint8_t { None = 0 , NotInitialized , InvalidParameter , InvalidAddress , BufferTooSmall , SerialError , Timeout , BadCrc , InvalidFrame , ModbusException , UnsupportedRequest , ResponseMismatch , AsciiBadResponse }
	Driver-level error codes. More...

enum class	ModbusExceptionCode : uint8_t { None = 0x00 , IllegalFunction = 0x01 , IllegalDataAddress = 0x02 , IllegalDataValue = 0x03 , ServerDeviceFailure = 0x04 , Acknowledge = 0x05 , ServerDeviceBusy = 0x06 }
	Exception code of a Modbus exception reply (function code \| 0x80, one code byte). More...

enum class	Gas : uint8_t { Air = 0 , Argon = 1 , CarbonDioxide = 2 , Nitrogen = 3 , Oxygen = 4 , NitrousOxide = 5 , Hydrogen = 6 , Helium = 7 , Methane = 8 }
	Index into the BASIS-2 calibrated gas table. More...

enum class	FlowUnits : uint8_t { SCCM = 0 , NCCM = 1 , SLPM = 2 , NLPM = 3 , SmL_s = 4 , NmL_s = 5 , SmL_m = 6 , NmL_m = 7 , SL_h = 8 , NL_h = 9 , SCCS = 10 , NCCS = 11 , Sm3_h = 12 , Nm3_h = 13 , Sm3_d = 14 , Nm3_d = 15 , SCIM = 16 , SCFM = 17 , SCFH = 18 , SCFD = 19 , Unknown = 0xFF }
	Flow-unit identifier read from instrument register 49. More...

enum class	BaudRate : uint8_t { Bps_4800 = 0 , Bps_9600 = 1 , Bps_19200 = 2 , Bps_38400 = 3 , Bps_57600 = 4 , Bps_115200 = 5 }
	Baud-rate codes for register 21 (datasheet "Changing the Baud Rate"). More...

enum class	SetpointSource : uint8_t { Analog = 0 , DigitalSaved = 1 , DigitalUnsaved = 2 }
	Setpoint source — register 516 (controllers only). More...

enum class	TotalizerLimitMode : uint8_t { SaturateNoError = 0 , ResetNoError = 1 , SaturateWithOvr = 2 , ResetWithOvr = 3 }
	Totalizer overflow behaviour — register 54. More...

Functions
const char *	GetDriverVersion () noexcept
	Driver version string (from generated alicat_basis2_version.h).

constexpr std::string_view	ToString (DriverError e) noexcept
	Convert a DriverError to a stable human-readable string (no allocation).

constexpr std::string_view	ToString (ModbusExceptionCode c) noexcept
	Convert a ModbusExceptionCode to a stable human-readable string (no allocation).

constexpr std::string_view	GasShortName (Gas g) noexcept

constexpr std::string_view	ToString (FlowUnits u) noexcept

constexpr uint32_t	BaudRateToBps (BaudRate b) noexcept

Variables
constexpr uint8_t	kBroadcastAddress = 0

constexpr uint8_t	kMaxModbusAddress = 247

constexpr uint16_t	kMagicTare = 0xAA55

constexpr uint16_t	kMagicFactoryRestore = 0x5214

constexpr uint16_t	kDefaultTimeoutMs = 200

constexpr uint16_t	kInterFrameDelayMs = 5

constexpr uint32_t	kDefaultBusBaudBps = 38400
	Baud rate the driver assumes for the inter-frame gap until told otherwise (the instrument's factory default, manual Rev 4 p.

Enumeration Type Documentation

◆ BaudRate

enum class alicat_basis2::BaudRate : uint8_t

strong

Baud-rate codes for register 21 (datasheet "Changing the Baud Rate").

The numeric value is what the instrument expects on the wire; the BaudRateToBps helper converts it to a real bits-per-second number for driver-side serial-port reconfiguration.

Enumerator
Bps_4800
Bps_9600
Bps_19200
Bps_38400	Factory default.
Bps_57600
Bps_115200

◆ DriverError

enum class alicat_basis2::DriverError : uint8_t

strong

Driver-level error codes.

Every public Driver entry point returns one of these in its result type. The values are stable and may be used directly in CAN/MQTT payloads.

Enumerator
None	Operation succeeded.
NotInitialized	Driver not initialized yet.
InvalidParameter	Out-of-range argument.
InvalidAddress	Modbus address outside 1..247.
BufferTooSmall	Provided buffer is too small for the response.
SerialError	Serial transport-layer error (HW failure).
Timeout	No response within the configured timeout.
BadCrc	CRC-16 mismatch on received Modbus frame.
InvalidFrame	Frame too short, wrong function code, etc.
ModbusException	Slave returned a Modbus exception PDU.
UnsupportedRequest	Slave does not implement this register/command.
ResponseMismatch	Echo doesn't match request (function 6/16).
AsciiBadResponse	ASCII reply not parseable.

◆ FlowUnits

enum class alicat_basis2::FlowUnits : uint8_t

strong

Flow-unit identifier read from instrument register 49.

The numeric value matches the datasheet table verbatim.

Enumerator
SCCM
NCCM
SLPM
NLPM
SmL_s
NmL_s
SmL_m
NmL_m
SL_h
NL_h
SCCS
NCCS
Sm3_h
Nm3_h
Sm3_d
Nm3_d
SCIM
SCFM
SCFH
SCFD
Unknown

◆ Gas

enum class alicat_basis2::Gas : uint8_t

strong

Index into the BASIS-2 calibrated gas table.

The instrument is factory-calibrated for these 9 gases; the value is what the device expects on register 2100 / GS ASCII command.

Enumerator
Air
Argon
CarbonDioxide
Nitrogen
Oxygen
NitrousOxide
Hydrogen
Helium
Methane

◆ ModbusExceptionCode

enum class alicat_basis2::ModbusExceptionCode : uint8_t

strong

Exception code of a Modbus exception reply (function code | 0x80, one code byte).

Modbus Application Protocol V1.1b3, section 7. The BASIS-2 manual (Rev 4, "Communicating Via Modbus-RTU", p. 18) names the illegal data address ("Bad Address") reply for undefined registers. Driver::GetLastException() returns the code of the last exception reply.

Enumerator
None	The last transaction got no exception reply.
IllegalFunction	Function code not supported.
IllegalDataAddress	Register not implemented ("Bad Address").
IllegalDataValue	Value not accepted.
ServerDeviceFailure	Unrecoverable error in the instrument.
Acknowledge	Accepted, long-running.
ServerDeviceBusy	Busy; retry later.

◆ SetpointSource

enum class alicat_basis2::SetpointSource : uint8_t

strong

Setpoint source — register 516 (controllers only).

Analog — 0–5 V or 4–20 mA on pin 1 controls the setpoint; digital S / register-2053 writes are ignored. DigitalSaved — most recent digital setpoint is persisted to flash and used at next power-up. Avoid frequent writes (the datasheet warns of NVM wear). DigitalUnsaved — digital setpoint is volatile (lost on power loss). Recommended whenever the setpoint changes faster than once per few minutes.

Enumerator
Analog
DigitalSaved
DigitalUnsaved

◆ TotalizerLimitMode

enum class alicat_basis2::TotalizerLimitMode : uint8_t

strong

Totalizer overflow behaviour — register 54.

Enumerator
SaturateNoError
ResetNoError
SaturateWithOvr
ResetWithOvr

Function Documentation

◆ BaudRateToBps()

constexpr uint32_t alicat_basis2::BaudRateToBps ( BaudRate b )

constexprnoexcept

◆ GasShortName()

constexpr std::string_view alicat_basis2::GasShortName ( Gas g )

constexprnoexcept

◆ GetDriverVersion()

const char * alicat_basis2::GetDriverVersion ( )

inlinenoexcept

Driver version string (from generated alicat_basis2_version.h).

◆ ToString() [1/3]

constexpr std::string_view alicat_basis2::ToString ( DriverError e )

constexprnoexcept

Convert a DriverError to a stable human-readable string (no allocation).

◆ ToString() [2/3]

constexpr std::string_view alicat_basis2::ToString ( FlowUnits u )

constexprnoexcept

◆ ToString() [3/3]

constexpr std::string_view alicat_basis2::ToString ( ModbusExceptionCode c )

constexprnoexcept

Convert a ModbusExceptionCode to a stable human-readable string (no allocation).

Variable Documentation

◆ kBroadcastAddress

constexpr uint8_t alicat_basis2::kBroadcastAddress = 0

inlineconstexpr

◆ kDefaultBusBaudBps

constexpr uint32_t alicat_basis2::kDefaultBusBaudBps = 38400

inlineconstexpr

Baud rate the driver assumes for the inter-frame gap until told otherwise (the instrument's factory default, manual Rev 4 p.

18).

◆ kDefaultTimeoutMs

constexpr uint16_t alicat_basis2::kDefaultTimeoutMs = 200

inlineconstexpr

◆ kInterFrameDelayMs

constexpr uint16_t alicat_basis2::kInterFrameDelayMs = 5

inlineconstexpr

Deprecated:: Never used by the driver. The inter-frame gap is computed from the bus baud rate: modbus::InterFrameGapUs(), Driver::SetBusBaudRate().

◆ kMagicFactoryRestore

constexpr uint16_t alicat_basis2::kMagicFactoryRestore = 0x5214

inlineconstexpr

◆ kMagicTare

constexpr uint16_t alicat_basis2::kMagicTare = 0xAA55

inlineconstexpr

◆ kMaxModbusAddress

constexpr uint8_t alicat_basis2::kMaxModbusAddress = 247

inlineconstexpr

Namespaces

Classes

Enumerations

Functions

Variables

Enumeration Type Documentation

◆ BaudRate

◆ DriverError

◆ FlowUnits

◆ Gas

◆ ModbusExceptionCode

◆ SetpointSource

◆ TotalizerLimitMode

Function Documentation

◆ BaudRateToBps()

◆ GasShortName()

◆ GetDriverVersion()

◆ ToString() [1/3]

◆ ToString() [2/3]

◆ ToString() [3/3]

Variable Documentation

◆ kBroadcastAddress

◆ kDefaultBusBaudBps

◆ kDefaultTimeoutMs

◆ kInterFrameDelayMs

◆ kMagicFactoryRestore

◆ kMagicTare

◆ kMaxModbusAddress