176461 User Manual.book

MicroLogix 1500 Programmable Controllers User Manual

IIM - Immediate Input with Mask

Immediate Input w/Mask

Slot I:0.0

Mask

Length

N7:0

1

Instruction Type: output

Note:

This instruction is used for the MicroLogix 1500 on-board I/O only. It is not designed to be used with expansion I/O.

Table 22-1: Execution Time for the IIM Instruction

When Rung Is:

True

22.06

µ s

False

0.00

µ s

The IIM instruction allows you to selectively update input data without waiting for the automatic input scan. This instruction uses the following operands:

• Slot - This operand defines the location where data is obtained for updating the input file. The location specifies the slot number and but the word where data is to be obtained. For example, if slot = I:0, input data from slot 0 starting at word 0 is masked and placed in input data file I:0 starting at word 0 for the specified length.

If slot = I0.1, word 1 of slot 0 is used, and so on.

Important:

Slot 0 is the only valid slot number that can be used with this instruction. IIM cannot be used with expansion I/O.

• Mask - The mask is a hex constant or register address containing the mask value to be applied to the slot. If a given bit position in the mask is a “1”, the corresponding bit data from slot is passed to the input data file. A “0” prohibits corresponding bit data in slot from being passed to the input data file. The mask value can range from 0 to 0xFFFF.

Bit

Real Input

Mask

Input Data File

15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

Input Word

0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1

Data is Not Updated Updated to Match Input Word

• Length - This is the number of masked words to transfer to the input data file.

22-2

Input and Output Instructions

Addressing Modes and File Types can be used as shown below:

Table 22-2: IIM Instruction Valid Addressing Modes and File Types

For definitions of the terms used in this table see “Using the Instruction Descriptions” on page 11-2.

Data Files Function Files

Address

Mode

Parameter

Address

Level

Slot

Mask

Length

• •

•

• • •

•

• • • •

•

22-3