4 Teaching
4.8 Local Variables
4-74
HW1485509
HW1485509
However, there are some cases where conversion of parameter types is
allowed. For example, if a B Variable is passed in Call Instruction, it can
always be copied into a LD Variable in GetArgument as the allowable
range of the LD Variable is larger than the B Variable. If a D Variable is
passed in Call Instruction, it can be copied into a LB Variable in
GetArgument as long as the value of the D variable is between 0-255
which is the allowable range of a LB Variable. Otherwise, the same alarm
shown above will be generated.
The following table shows the available type conversions.
Argument Type passed from Call Instruction
Const
String
Const
Integer
B/LB I/LI D/LD R/LR S/LS P/LP
Result Type
in GetArgument
Instruction
LB NO YES* YES YES* YES* NO NO NO
LI NO YES* YES YES YES* NO NO NO
LD NO YES YES YES YES NO NO NO
LR NO YES YES YES YES YES NO NO
LS YES NO NO NO NO NO YES NO
LP NO NO NO NO NO NO NO YES
*Value of variable passed in Call Instruction must be within the range of the
variable assigned in GetArgument.
Call
Arg1=B001
GetArgument
Arg1=LD001
Allowed
Parent Job Child Job
Call
Arg2=D001
GetArgument
Arg2=LB001
Allowed if value of
D001 is between
0-255
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