<GMA> array

Use the predefined <GMA> array to conveniently process multiaxis movement <MULTIGOTO> command in the technology program and in the mask of the command. <GMA> array is initialized directly before the <MULTIGOTO> technology command is processed.

Every item of <GMA> array corresponds to an controlled coordinate of the machine scheme. Items of the <GMA> array can be added manually using the Postprocessor generator interface or imported directly from CAM system machine scheme.

Optionally, coordinates can be added to <GMA> array during postprocessor execution using following operator syntax:

GMA(<AxisName> {,<RegisterName>})

Here <AxisName> is a legal expression that returns a string. The new coordinate name will be set to <AxisName>, use it to access the new item. Optional paramter <RegisterName> is the name of the register associated with the new.

Example:

GMA(“AxisXPos”)

Use the name of a coordinate to access it's <GMA> properties:

GMA[<AxisName>].<Property>

Or for masks:

Here <AxisName> is a legal string expression that must be a valid coordinate name. In the following example the name of the coordinate <AxisXPos> is used to access the coordinate current value:

GMA[“AxisXPos”].Vn ! Vn – coordinate current value

GMA Structure

<GMA> array item has the following structure:

GMA[<AxisName>].OutFlag

GMA[<AxisName>].Vn

GMA[<AxisName>].Vp

GMA[<AxisName>].Axis

GMA[<AxisName>].Reg

GMA[<AxisName>].TurnCount

GMA[<AxisName>].Dir

<GMA[<AxisName>].OutFlag> is an <Integer> field that is assigned values 1 or 0. Use this flag to determine whether the coordinate named <AxisName> is listed in the given <MULTIGOTO> command. <GMA[<AxisName>].OutFlag> has the value of 1 (the flag is set) if there is a coordinate named is <AxisName> in the given <MULTIGOTO> command, otherwise the flag is 0.
<GMA[<AxisName>].Vn> is a <Real> field and it's value is the new value of the coordinate <AxisName> set by <MULTIGOTO> command. Use the <Vn> field to read or set the new coordinate value.
<GMA[<AxisName>].Vp> is a <Real> field that contains the value of <AxisName> coordinate assigned by the previous <MULTIGOTO> command. Use the <Vp> field to read or set the previous coordinate value.
<GMA[<AxisName>].Axis> is a <String> field that is the name of the coordinate and is equal to <AxisName>. The field is read-only.
<GMA[<AxisName>].Reg> is a <String> field and it's value is the name of the register associated with the coordinate. The field is read-only.
<GMA[<AxisName>].TurnCount> is an <Integer> field that is assigned the number of full turns of a rotatable axis. The field is read-only.
<GMA[<AxisName>].Dir> is an <Integer> value that is assigned +1 if the value of the coordinate is increasing, otherwise it is set to -1. The field is read-only.

Use <TurnCount> and <Dir> fields to process the movement of rotatable axes. CAM system passes the movements of rotatable axes in absolute values, whereas some NC-systems accept only values in bound ranges like 0º to 360º or 180º до -180º for those coordinates. Use the <Machine axes parameters> dialog to define the bounds and ranges parameters of rotatable axes. If angle reduction is defined for a given coordinate then when processing <MULTIGOTO> command the system will reduce the coordinate value <Vn> to specified range, assign the <TurnCount> field the number of full revolutions of the coordinate and set the sign of the <Dir> field depending on the previous (not reduced) value of the coordinate.

Here are a few examples illustrating how the system initializes the properties of <GMA> array items when processing <MULTIGOTO> technology command. Suppose rotatable axis C (<AxisCPos>) is bound to values from 0º to 360º.

Command:

MULTIGOTO COUNT 4, AxisXPos(18) 80, AxisYPos(20) 19.877,

AxisZPos(22) -200, AxisCPos(24) 0

<GMA> array for the <MULTIGOTO> command
Coordinate name	OutFlag	Vn	Vp	Axis	Reg	TurnCount	Dir
AxisXPos	1	80	-//-//-	“AxisXPos”	“X”	-//-//-	-//-//-
AxisYPos	1	19.877	-//-//-	“AxisYPos”	”Y”	-//-//-	-//-//-
AxisZPos	1	-200	-//-//-	“AxisZPos”	”Z”	-//-//-	-//-//-
AxisCPos	1	0	-//-//-	“AxisCPos”	”C”	-//-//-	-//-//-

«-//-//-» sign indicates that the values of the properties of coordinates cannot be determined because there is no information of the previous command.

Command:

MULTIGOTO COUNT 1, AxisCPos(24) 270

<GMA> array for the <MULTIGOTO> command
Coordinate name	OutFlag	Vn	Vp	Axis	Reg	TurnCount	Dir
AxisXPos	0	80	80	“AxisXPos”	”X”	-//-//-	-//-//-
AxisYPos	0	19.877	19.877	“AxisYPos”	”Y”	-//-//-	-//-//-
AxisZPos	0	-200	-200	“AxisZPos”	”Z”	-//-//-	-//-//-
AxisCPos	1	270	0	“AxisCPos”	”C”	0	+1

Command:

MULTIGOTO COUNT 2, AxisZPos(22) 250, AxisCPos(24) -745

<GMA> array for the <MULTIGOTO> command
Coordinate name	OutFlag	Vn	Vp	Axis	Reg	TurnCount	Dir
AxisXPos	0	80	80	“AxisXPos”	”X”	-//-//-	-//-//-
AxisYPos	0	19.877	19.877	“AxisYPos”	”Y”	-//-//-	-//-//-
AxisZPos	1	250	-200	“AxisZPos”	”Z”	-//-//-	-//-//-
AxisCPos	1	335	270	“AxisCPos”	”C”	2	-1

In the last example the system applied angle reduction for the <AxisCPos(C)> coordinate. The value passed by CAM system «-745 º» is reduced to the range from 0º to 360º by the following rules:

TurnCount = |(Vn’ - Vp’) \ 360|

TurnCount = |(-745 -270) \ 360| = 2

Dir = Sgn(Vn’-Vp’)

Dir = Sgn(-745 -270) = -1

Vn = Vn’ – (Vn’ \ 360)*360, if Vn’ > 360

Vn = Vn’ – (Vn’ \ 360)*360 + 360, if Vn’ < 0

Vn = -745 – (-745\360)*360 + 360 = 335

<Vn’> – the current not reduced value of the coordinate, <Vp’> – previous not reduced value of the coordinate.

The following is an example of a simple <MULTIGOTO> command program that uses the <GMA> array:

program MultiGoto

! Use the GMA fields to assign

! respective registers their new values

if GMA["AxisXPos"].OutFlag>0 then

X = GMA["AxisXPos"].Vn

if GMA["AxisYPos"].OutFlag>0 then

Y = GMA["AxisYPos"].Vn

if GMA["AxisZPos"].OutFlag>0 then

Z = GMA["AxisZPos"].Vn

if GMA["AxisCPos"].OutFlag>0 then

C = GMA["AxisCPos"].Vn

! Output the formed values into the NC-program

OutBlock

end