DataTypes Sheet¶

This sheet describes data types that can then be used in the definition of parameters and command arguments.

type name (required)

Name of the type used as a reference in the parameter and command sheets.

eng type (required)

Engineering type. One of:

uint: unsigned 32 bit integer
uint64: unsigned 64 bit integer
int: signed 32 bit integer
int64: signed 64 bit integer
enumerated: enumeration (integer to string)
float: 32 bit floating point number
double: 64 bit floating point number
boolean: true or false
string: text value
binary: byte array
time: absolute time

It is also possible to define an aggregate or array type.

See: Engineering Types.

raw type

See: Encoding and Raw Types.

A parameter when extracted from a binary packet has two forms: a raw value and an engineering value. The extraction from the raw packet is performed according to the encoding, whereas the conversion from raw to engineering value is performed by a calibrator.

Raw types are optional for use with parameters that do not require encoding. For example because they are already extracted. Then Yamcs can only do their calibration. Or it can be that a parameter is already calibrated, then it can still be specified here to be able to associate alarms.

encoding

See: Encoding and Raw Types.

eng unit

Unit of measure. For informational purpose only.

calibration

Reference to a calibrator defined in the Calibration sheet. Leave empty if no calibration is applied.

initial value

Initial (default) value given to a parameter or command argument.

Note that this value can be overwritten for specific parameters, or command arguments using a column of the same name in the Commands and Parameters sheets.

The value must be understandable for the used engineering type.

For binary, use a hexadecimal notation.

For booleans, use a value of true or false.

For arrays, specify a value in JSON format: [-3, -2.4, 5].

For aggregates, specify a value in JSON format: {member1: 1, member2: 2}.

description

A description for the parameter or command argument. Should be one line.

long description

Long textual description. In Markdown format.

Encoding and Raw Types¶

The columns raw type and encoding describe how the parameter is encoded in the binary packet. All types are case-insensitive.

Unsigned Integers¶

Raw type: uint

Encoding:

Encoding	Description
`unsigned(<n>,<BE\|LE>)`	unsigned integer
`<n>`	shortcut for `unsigned(<n>,BE)`

Where:

n is the size in bits
LE = little endian
BE = big endian

Signed Integers¶

Raw type: int

Encoding:

Encoding	Description
`twosComplement(<n>,<BE\|LE>)`	two's complement encoding
`signMagnitude(<n>,<BE\|LE>)`	sign magnitude encoding - first (or last for LE) bit is the sign, the remaining bits represent the magnitude (absolute value).
`<n>`	shortcut for `twosComplement(<n>,BE)`

Where:

n is the size in bits
LE = little endian
BE = big endian

Floats¶

Raw type: float

Encoding:

Encoding	Description
`ieee754_1985(<n>,<BE\|LE>)`	IEE754_1985 encoding
`<n>`	shortcut for `ieee754_1985(<n>,BE)`

Where:

n is the size in bits
LE = little endian
BE = big endian

Booleans¶

Raw type: boolean

Encoding: Leave empty. 1 bit is assumed.

String¶

Raw type: string

Encoding:

Encoding	Description
`fixed(<n>, <charset>)`	fixed size string. The string has to start at a byte boundary inside the container.
`PrependedSize(<x>, <charset>)`	string whose length in bytes is specified by the first `x` bits of the array
`<n>`	shortcut for `fixed(<n>)`
`terminated(<0xBB>, <charset><m>)`	terminated string

Where:

n is the size in bits. Only multiples of 8 are supported.

x is the size in bits of the size tag. Only multiples of 8 are supported. The size must be expressed in bytes.

charset is one of the charsets supported by java (UTF-8, ISO-8859-1, etc). Default: UTF-8.

0xBB specifies a byte that is the string terminator. Pay attention to the parameters following this one; if the terminator is not found the entire buffer will be consumed.

Binary¶

Raw type: binary

Encoding:

Encoding	Description
`fixed(<n>)`	fixed size byte array
`PrependedSize(<x>)`	byte array whose size in bytes is specified in the first `x` bits of the array
`<n>`	shortcut for `fixed(<n>)`

Where:

n is the size in bits. Only multiples of 8 are supported and it has to start at a byte boundary.

x is the size in bits of the size tag. Note that while x can be any number <= 32, the byte array has to start at a byte boundary.

Custom¶

Raw type: any

Encoding: custom(<n>,algorithm)

The decoding will be performed by a user defined algorithm.

<n> is optional and may be used to specify the size in bits of the entry in the container (in case the size is fixed) - it is used for optimizing the access to the parameters following this one.
algorithm the name of the algorithm - it has to be defined in the Algorithms sheet

Engineering Types¶

Engineering types describe a parameter in its processed form (i.e. after any calibrations). All types are case-insensitive.

Depending on the combination of raw and engineering type, automatic conversion is applicable. For more advanced use cases, define and refer to a calibrator in the Calibration sheet.

Type	Description	Automatic Conversion
`uint`	Unsigned 32 bit integer - it corresponds to `int` in Java.	From `int`, `uint` or `string`
`uint64`	Unsigned 64 bit integer - it corresponds to `long` in Java.	From `int`, `uint` or `string`
`int`	Signed 32 bit integer - it corresponds to `int` in Java.	From `int`, `uint` or `string`
`int64`	Signed 64 bit integer - it corresponds to `long` in Java.	From `int`, `uint` or `string`
`string`	Character string - it corresponds to `String` in Java.	From `string`
`float`	32 bit floating point number - it corresponds to `float` in Java.	From `float`, `int`, `uint` or `string`
`double`	64 bit floating point number - it corresponds to `double` in Java.	From `float`, `int`, `uint` or `string`
`enumerated`	A kind of string that can only be one out of a fixed set of predefined state values. It corresponds to `String` in Java.	From `int` or `uint`. A Calibrator is required.
`boolean`	A binary true/false value - it corresponds to 'boolean' in Java.	From any raw type. Values equal to zero, all-zero bytes or an empty string are considered false.
`binary`	Byte array - it corresponds to `byte[]` in Java.	From `binary` only.