MC-Basic:pls.HWASSISTANCE

The high-accuracy PLS timing mode is activated by HWAssistance.

• PLS High Accuracy On (<pls>.HWAssistance = <value>)
  

When high-accuracy mode is active, the Product software extrapolates the exact time at which the axis will reach the PLS position, based on its current position, velocity and acceleration, and sets an output event for that time.

If HWAssistance is active, the timing of the PLS output switch will be computed to an accuracy of microseconds.

The exact timing of the PLS switch is computed according to the current velocity and acceleration values of the samples before and after the PLS position.

In instances of constant acceleration or linear acceleration change between the two samples, the timing of the PLS is computed exactly to ±1µs.

• PLS High Accuracy Off (<pls>.HWAssistance = 0)

When HWAssistance is not active (normal PLS), the PLS outputs are toggled at the moment the PLS source crosses the PLS position.
The timing of the PLS switch is always an integer number of motion samples; therefore, the timing accuracy of the PLS is equivalent to the motion bus cycle.

	NOTE
	With fw version 4.5.29 and before, the position command delay of PositionErrorDelay-2 samples will be taken into account as hard-coded expression. This means that in case of PositionErrorDelay = 3, when the PLSposition is passed, the output will be triggered after 1 sample delay plus Δt, the inter-sample delay.

	NOTE
	Hwassistance is available only in systems that have the hardware that support this functionality

Short form

<pls>.HWAssistance

Syntax

?<pls>. HWAssistance

Availability

Versions 4.21.2 and higher

Type

Long

Range

0  - no HW assistance
1  - el2258 time-stamping module
2  - CDHD2 PCOM1/PCOM2

Default

FALSE

Scope

Configuration, Task or Terminal

Limitations

• Available only in systems with hardware that supports this functionality timestamping module el2258 or CDHD2 PCOM1/PCOM2
  
• Modal/Nodal
  

Examples

CDHD2 Setup
1.Add objects 0x2191.0/0x2205.1 (PCOM1) or 0x2192.0/0x2206.1 (PCOM2) to TXPDO
2.Two (2) additional outputs above digital outputs (for instance, 0x1008 and 0x1009 if CDHD2 is the first device on the network) will be implicitly mapped into sys.dout
-->?ver
Version Number = MULTIBUS 0.4.21.2r1-C2 , Date = Nov 27 2022 [15:02:17]
-->common shared HWPLS1 as PLS a1 sys.DOut.1008
-->sys.DOut.1008 = 0 'test that output is available and can be reached
-->HWPLS1.HWAssistance=2
-->?plslist
PlsName=HWPLS1,AxisName=A1,Output=sys.dout.1008,HWAssistance=TRUE
?HWPLS1.PLSPropagationDelay=0

See Also

• COMMON SHARED ... AS PLS