Set Flexible Encoder Source Info

Sets the specified information in the named absolute or companion source.

Block ID

Set Source Info





Sets the specified information in the named absolute or companion source. A drop down menu is used to specify what information is to be modified. Multiple instances of the block can be used within a model, each of which can modify the same or different data for a source.

Default Key Tolerance

This attribute modifies the current value of the DefaultKeyTolerance attribute being used by the encoder pattern that this source is referencing. The high and low tolerance are specified, irrespective of whether the pattern was defined to use a symmetrical or asymmetrical key definition. The values are fixed point integers where 16 represents a tolerance of 1.0.

The DefaultKeyTolerance selection of the Get Source Info block can be used to recover the current value of the key and could be executed within a StartUp style trigger to recover the initial value prior to a set.

Ignore Halfcycle Companion

An absolute source typically utilizes a halfcycle companion to resolve what the current halfcycle state is at a particular instance in time. An absolute source typically queries the halfcycle companion each time it is to re-synchronize, which is any time that it observes a unique key. A halfcycle fault is reported by the absolute source when the expected halfcycle state does not equate to the state reported by the halfcycle companion. The encoder position is phase shifted by 360degCA when a halfcycle error is observed.

Halfcycle companion faults can lead to an incorrect halfcycle state report being made. This is particularly true with some single tooth encoders, which will falsely report state as they are transitioning to a signal loss condition. This is because the source continues to be used while it is in loss, but before the absolute source has been able to detect that this has occurred. A phase shift introduced because of this false report can have a detrimental impact on engine operation.

The Ignore Halfcycle Companion attribute has been introduced to allow an application to combat this problem. An absolute source will ignore the halfcycle state reported by its halfcycle companion and instead use its internally tracked halfcycle state. However the internally tracked position is only valid once it has been initialized and so attempts to set the Ignore Halfcycle Companion attribute to true before the source has achieved synchronization will be ignored. A true setting is also ignored if the absolute source is in error. Additionally, a previously applied setting of true will revert to false if the absolute source observes any errors. The setting is ignored and reverts because encoder errors can impact the reliability of the tracked halfcycle state.

The current state can be recovered via the Get Source Info block.

Block Parameters

Parameter Field Values Comments/Description
Reference Source Name Alpha-numeric text, quote enclosed The name of the absolute or companion source that is to be modified.
Data Dropdown Data selected from:
Default Key Tolerance
Ignore Halfcycle Companion