MCP_CamTableSelect – Cam definition

Block SymbolLicensing group: MOTION CONTROL
PIC

Function Description

The MCP_CamTableSelect block defines a cam profile. The definition is similar to MC_PositionProfile block, but the time axis is replaced by master position axis. There are also two possible ways for cam profile definition:

1. sequence of values: given sequence of master-slave position pairs. In each master position interval, value of slave position is interpolated by 3rd-order polynomial (simple linear interpolation would lead to steps in velocity at interval border). Master position sequence is in array/parameter mvalues, slave position sequence is in array/parameter svalues. Master position sequence must be increasing.

2. spline: master position sequence is the same as in previous case. Each interval is interpolated by 5th-order polynomial p(x) = a5x5 + a4x4 + a3x3 + a2x2 + a1x + a0 where beginning of time-interval is defined for x = 0, end of time-interval holds for x = 1 and factors ai are put in array/parameter svalues in ascending order (e.g. array/parameter svalues contain 6 values for each interval). This method allows to reduce the number of intervals and there is special graphical editor available for interpolating curve synthesis.

For both cases the master position sequence can be equidistantly spaced in time and then the time array includes only first and last point.

Note 1: input CamTable which is defined in PLCOpen specification is missing, because all path data are set in the parameters of the block.

Note 2: parameter svalues must be set as a vector in all cases, e.g. text string must not include a semicolon.

Note 3: incorrect parameter value cSeg (higher then real size of arrays times and/or values) can lead to unpredictable results and in some cases to crash of the whole runtime execution (The problem is platform dependent and currently it is observed only for SIMULINK version).

Inputs

uMaster

Master axis reference

Reference

uSlave

Slave axis reference

Reference

Execute

The block is activated on rising edge

Bool

Outputs

yMaster

Master axis reference

Reference

ySlave

Slave axis reference

Reference

Done

Algorithm finished

Bool

Busy

Algorithm not finished yet

Bool

Error

Error occurred

Bool

ErrorID

Result of the last operation

Error

i ....

REXYGEN general error

CamTableID

Cam table reference (connect to MC_CamIn.CamTableID)

Reference

Parameters

alg

Algorithm for interpolation  2

Long (I32)

1 ....

Sequence of time/value pairs

2 ....

Sequence of equidistant values

3 ....

Spline

4 ....

Equidistant spline

nmax

Number of profile segments  3

Long (I32)

Periodic

Indicate periodic cam profile  on

Bool

camname

Filename of special editor data file (filename is generated by system if parameter is empty)

String

mvalues

Master positions where segments are switched  [0 30]

Double (F64)

sValues

Slave positions or interpolating polynomial coefficients (a0, a1, a2, ...)  [0 100 100 0]

Double (F64)

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