Allen-Bradley MicroLogix 1400 User Manual

Publication 1766-RM001A-EN-P - October 2008
Compare Instructions 193
MEQ - Mask Compare
for Equal
Instruction Type: input
The MEQ instruction is used to compare whether one value (source) is
equal to a second value (compare) through a mask. The source and the
compare are logically ANDed with the mask. Then, these results are
compared to each other. If the resulting values are equal, the rung state is
true. If the resulting values are not equal, the rung state is false.
For example:
The source, mask, and compare values must all be of the same data size
(either word or long word). The data ranges for mask and compare are:
• -32,768…32,767 (word)
• -2,147,483,648…2,147,483,647 (long word)
The mask is displayed as a hexadecimal unsigned value from 0000…FFFF
FFFF.
Addressing Modes and File Types can be used as shown in the following
table:
MEQ
Masked Equal
Source N7:0
0<
Mask N7:1
0000h<
Compare N7:2
0<
MEQ
Execution Time for the MEQ Instructions
Controller Data Size When Rung Is:
True False
MicroLogix 1400 word 6.2730 µs 0.1934 µs
long word 7.1602 µs 0.1780 µs
Source: Compare:
11111010000011001111111100000000
Mask: Mask:
11001111110000111100111111000011
Intermediate Result: Intermediate Result:
11001010000000001100111100000000
Comparison of the Intermediate Results: not equal
MEQ Instruction Valid Addressing Modes and File Types
For definitions of the terms used in this table see Using the Instruction Descriptions on page 92.
Parameter
Data Files
Function Files
(1)
CS - Comms IOS - I/O DLS - Data Log
Address
Mode
(2)
Address Level
O I S B T, C, R N F ST L MG, PD RI/RIX PLS RTC HSC PTOX, PWMX STI EII BHI MMI LCD Immediate Direct Indirect Bit Word Long Word Element
Source •••••• ••• ••••••••••• • •••
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Allen-Bradley MicroLogix 1400 Specifications

General

Brand	Allen-Bradley
Model	MicroLogix 1400
Category	Controller
Language	English