4MELFA-BASIC IV
 Detailed explanation of command words   4-182
Def Arch (Define arch)
[Function]
This instruction defines an arch shape for the arch motion movement corresponding to the Mva instruction.
[Format].
[Terminology]
<Arch  number> Arch motion movement pattern number. Specify a number from 1 to 4 using a con-
stant or a variable.
<Upward movement increment>
<Downward movement increment >
Refer to figure at right. It is pos-
sible to specify either a con-
stant or a variable.
<Upward evasion increment>
<Downward evasion increment>
<Interpolation type> Interpolation type for upward 
and downward movements. 
Linear/joint = 1/0
<Interpolation type 1> Detour/short cut = 1/0,
<Interpolation type 2> 3-axis XYZ/Equivalent rotation = 1/0
If any of the arguments besides the arch number is omitted, the default value is employed.
The default values are set by the following parameters. Check the corresponding parameters to see the values; 
it is also possible to modify the values.
Vertical multi-joint robot(RV-6SDL, etc.)
 Horizontal multi-joint robot(RH-12SDH **, etc.)
[Reference Program]
1 Def Arch 1,5,5,20,20
2 Mva P1,1 'Performs the arch motion movement defined in the shape definition in step 10.
3 Mva P2,2 'The robot moves according to the default values specified by the parameters.
[Explanation]
(1) If the Mva instruction is executed without the Def Arch instruction, the robot moves according to the arch 
shape specified by the parameters.
(2) Used to change the increments in a program, etc.
[Related instructions]
Mva (Move Arch), Accel (Accelerate), Ovrd (Override), Mvs (Move S)(Used as a reference for interpolation 
types 1 and 2)
Def[]Arch[]<Arch number>, [<upward movement increment>][<downward movement increment >],
[<Upward evasion increment>], [<downward evasion increment>], 
[<interpolation type>], [<interpolation type 1>, <interpolation type 2> ]
Parameter name Arch number
Upward movement 
increment (mm)
Downward movement 
increment (mm)
Upward evasion 
increment (mm)
Downward evasion 
increment (mm)
ARCH1S 1 0.0 0.0 30.0 30.0
ARCH2S 2 10.0 10.0 30.0 30.0
ARCH3S 3 20.0 20.0 30.0 30.0
ARCH4S 4 30.0 30.0 30.0 30.0
Parameter 
name
Arch 
number
Interpolation 
type
Interpolation 
type 1
Interpolation 
type 2
Parameter 
name
Arch 
number
Interpolation 
type
Interpolation 
type 1
Interpolation 
type 2
ARCH1T 1 1 0 0 ARCH1T 1 0 0 0
ARCH2T 2 1 0 0 ARCH2T 2 0 0 0
ARCH3T 3 1 0 0 ARCH3T 3 0 0 0
ARCH4T 4 1 0 0 ARCH4T 4 0 0 0
×
●
Downward 
movement 
increment
Downward 
evasion 
increment
Upnward 
evasion 
increment
Upnward 
movement 
increment