Signal¶

This chapter describes the Signal interface. The Signal interface provides access to parameters and variables.

Data type¶

A Signal has a ‘native’ data type. The data type of a Signal might be queried for display purposes, e.g. in controller agnostic tooling.

Not all data types have a unique accessor. A signal can be accessed by calling ValueDouble and ValueUint32 (for C#) or Read/WriteDouble and Read/WriteUint32 (for C++). For boolean, enum and mask signals Translations can be used to translate a signal value into human-readable enumerated string representation.

The Signal data types and accompanying accessor are listed in the following table:

Signal data types¶
Data type	Accessor type	Description
Uint8	Uint32	8-bit unsigned integer value
Int8	Double	8-bit signed integer value
Uint16	Uint32	16-bit unsigned integer value
Int16	Double	16-bit signed integer value
Uint32	Uint32	32-bit unsigned integer value
Uint64	Double	64-bit unsigned integer value
Int32	Double	32-bit signed integer value
Int64	Double	64-bit signed integer value
Double	Double	Double-precision floating-point value
Enum	Uint32	Enumeration, e.g. a state machine state.
Float	Double	Single precision floating-point value
Mask	Uint32	Individual bits each represent an individual condition or entity, e.g. error flags.
Bool	Uint32	True (1) or false (0)

ISignal.ValueDouble
ISignal.ValueUint32
ISignal.Translations

C++

ISignal::ReadDouble()
ISignal::WriteDouble()
ISignal::ReadUint32()
ISignal::WriteUint32()
ISignal::GetTranslations()

Access¶

A Signal can be Read-Only (R) or Read-Write (R/W). Whether a signal is writable can be retrieved using the IsWritable property on the Signal interface. Read-Write signals can also be configured via XML, this is described in Signal.

Signal access¶
Access	Description
Read-Only	Signals, which can be viewed and reported but cannot be edited.
Read-Write	Signals, which can be viewed, edited, and reported.

ISignal.IsWritable

C++

ISignal::IsWritable()

Bounds¶

The bounds state the maximum and minimum value a signal can have. The range can be limited due to the native data type of the implementation, or due to other restrictions. An exception is thrown when writing an out of bound value to a signal. The UpperBound and LowerBound properties on the Signal interface can be used to retrieve the bound values.

ISignal.LowerBound

ISignal.UpperBound

C++

ISignal::GetLowerBound()

ISignal::GetUpperBound()

Match conditions¶

A match condition is used to check whether a Signal has reached a certain value. The mask can be used when the user is only interested in a particular part of the Signal. Signal operator definitions explains the available conditions.

Signal operator definitions¶
Signal operator	Uint32 expression	Double expression
Smaller	`(signal & mask) < value`	`signal < value`
SmallerEqual	`(signal & mask) <= value`	`signal <= value`
Equal	`(signal & mask) == value`	`signal == value`
LargerEqual	`(signal & mask) >= value`	`signal >= value`
Larger	`(signal & mask) > value`	`signal > value`
NotEqual	`(signal & mask) != value`	`signal != value`
Change	`abs((signal & mask) - (signal_p & mask)) > value`	`abs(signal - signal_p) > value`
BitSetAny	`(signal & mask) != 0`	N/A
BitClearAny	`(signal & mask) != mask`	N/A
BitSetAll	`(signal & mask) == mask`	N/A
BitClearAll	`(signal & mask) == 0`	N/A
BitRiseAny	`(~signal_p & signal & mask) != 0`	N/A
BitFallAny	`( signal_p & ~signal & mask) != 0`	N/A
BitRiseAll	`(~signal_p & signal & mask) == mask`	N/A
BitFallAll	`(signal_p & ~signal & mask) == mask`	N/A

Note

signal indicates the current value of the signal. signal_p indicates the previous value of the signal.

There are no guarantees about callback order of independent callbacks registered with SubscribeMatch.

Locking¶

Under certain conditions, the motion software requires exclusive editing rights, such as for signals added to a Lockable Parameter set. When editing such a signal via an other method, an exception is thrown.