Bradley Smoker PLC-5 user manual Example Variable Explanation

Addressing I/O and Controller Memory 4-19

When you specify indirect addresses, follow these guidelines:

•You can indirectly address the file number, word number, or bit number.

•The substitute address must be one of the following types: N, T, C, R, B, I, O, or S. Any T, C, or R address must be a word-length sub-member address, such as T4:0.ACC.

•Enter the pointer address in brackets [ ].

Example	Variable	Explanation
N[N7:0]:0	File number	The file number is stored in integer address
		N7:0.
N7:[C5:7.ACC]	Structure number	The word number is the accumulated value
		of counter 7 in file 5.
B3/[I:017]	Bit number	The bit number is stored in input word 17.
N[N7:0]:[N9:1]	File and word number	The file number is stored in integer address
		N7:0 and the word number in integer
		address N9:1.

ATTENTION

If you indirectly address the input or output image table, the value you specify in the integer file that you use for the indirection (the pointer) is converted to octal when executed by the instruction.

For example, if you enter O:[N7:0] and N7:0 contains the value 10, the value at N7:0 is converted to octal and the resulting address is O:012, not O:010.

To monitor for invalid indirect addresses, condition the rung with the indirect address with a limit test of the indirect address to ensure that the address stays within the intended range. This is especially advisable if the PLC-5 controller has no control over the indirect address, such as the value is determined by values from an I/O module or a peer controller.

Publication 1785-UM012D-EN-P - July 2005