Modifying A Symbol With An Index Register - Delta AH Series Operation Manual

Ch a pt er 5 Un d er s t a n d in g Com m on D e v ic e s
AH Motion Controller CPU
Data type
Device assigned by users Device assigned by the system
number of devices in an array conforms to the size of the array.
String N/A
*1. Please refer to ISPSoft User Manual for more information about setting a range of devices which can be assigned
automatically.
*2. A symbol representing a function block definition has a special significance. Please refer to ISPSoft User manual for
more information.
*3. X0.0 and Y0.1 are bits in the word devices X and Y. Please refer to ISPSoft User manual for more information.

5.4.5 Modifying a Symbol with an Index Register

You are allowed to use index registers (E device) in ISPSoft to modify a symbol. The E devices are like general 16-bit data
registers.You can write data into the E devices and read data from the E devices freely. If a E device is used as a general
register, it can only be used in a 16-bit instruction. The modification of a symbol by an index register is represented by the
format: Identifier@Index register. If an E device is used to modify an operand, it can be used in a 16-bit instruction or a
32-bit instruction.
Please refer to the program below. The device assigned to VAR_0 is D0. The data stored in an index register indicates the
offset for the symbol which the index register modifies. If the value in the index register E0 is 2, VAR_0@ E0 indicates that
2 is added to the device address (D0) assigned to VAR_0, that is, VAR_0@E0 represents D2. If M0 is ON, the value in E0
will be 2, the value in E1 will be 3, and the value in D2 will be moved to D103.
5_
Besides, if the value in an index register is changed, the device which actually operates differs from the original device. As
a result, if the original device is not used in the program, the final value in the original device is retained. In the figure
below, if the value in E0 is 3, the value in D2 will be moved to D103. When the value in E0 is changed from 3 to 4, the
value in D2 will be moved to D104, and the value in D103 will remain unchanged.
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