Bradley Smoker PLC-5 user manual Addressing as It Relates to an I/O Terminal

4-2Addressing I/O and Controller Memory

The figure below shows the relationship between an I/O terminal and its location in controller memory.

I/O Addressing as It Relates to an I/O Terminal

rack number 01 I/O group number 4

A

B

C

D 00 01 02 03 04 05 06 07 10 11 12 13 14 15

16 04

17 E

Input Module (1771-IAD)

																	rack number 01
																	I/O group number 5
																word
																address
17	16	15	14	13	12	11	10	07	06	05	04	03	02	01	00
					Output Image Table											00
																	A
																	B
																05	C
17	16	15	14	13	12	11	10	07	06	05	04	03	02	01	00		D
																	00
																	01
																	02
																07	03
																	04
																	05
																	06
					Input Image Table											00	07
																	10
																	11
																	12
																	13
																	14
17	16	15	14	13	12	11	10	07	06	05	04	03	02	01	00	04	15
																	16
																	17
																	E
																07	Output Module
																	(1771-OAD)
	I:014														O:015
																(	)
				12													07

Notice how input and output image file addresses correspond to hardware.

I:014/12

I for input or O for output 2-digit I/O rack number

I/O group number (0-7)

input or output number (0-7,10-17) (bit)

I/O image table is addressed octally.

Now that you are familiar with how controller memory is segmented to address a specific I/O terminal, the next section explains available addressing modes. These modes let you define the relationship between an I/O chassis slot and an I/O group (16 input bits and 16 output bits).

Publication 1785-UM012D-EN-P - July 2005