Allen-Bradley MicroLogix 1400 Instruction Manual page 292

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290 Sequencer Instructions
SQC 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
File • • •
Mask • • •
Source • • •
Control
Length
Publication 1766-RM001A-EN-P - October 2008
.
TIP
• Source - This is the value that is compared to file.
• Control - This is a control file address. The status bits, stack length,
and the position value are stored in this element. The control
element consists of 3 words:
15 14 13
Word 0 (1) --
EN
Word 1 Length - contains the number of steps in the sequencer reference file.
Word 2 Position - the current position in the sequence
(1) EN - Enable Bit is set by a false-to-true rung transition and indicates that the instruction is enabled.
(2) DN - Done Bit is set after the instruction has operated on the last word in the sequencer file. It is reset on the next
false-to-true rung transition after the rung goes false.
(3) ER - Error Bit is set when the controller detects a negative position value, or a negative or zero length value. When the
ER bit is set, the minor error bit (S2:5/2) is also set.
(4) FD - Found bit is set when the status of all non-masked bits in the source address match those of the word in the
sequencer reference file. This bit is assessed each time the SQC instruction is evaluated while the rung is true.
• Length - The length operand contains the number of steps in the
sequencer file (as well as Mask and/or Source if they are file data
types). The length of the sequencer can range from 1...256.
• Position - This is the current location or step in the sequencer file
(as well as Mask and/or Source if they are file data types). It
determines the next location in the stack to receive the current
comparison data. Position is a component of the control register.
The position can range from 0...255 for words and 0...127 for long
words. The position is incremented on each false-to-true transition.
Addressing Modes and File Types can be used as shown in the following
table:
Data Files
• • •
• • • •
• • • •
(2)
If mask is direct or indirect, the position selects the location in the
specified file.
12 11 10 9
(2) -- (3) not used
DN ER
Function Files
8 7 6 5 4 3 2 1 0
(4) not used
FD
Address
Address Level
(1)
Mode
• • •
• • • •
• • •
•
• •
•
•
•
•