Allen-Bradley MicroLogix 1200 Reference Manual page 187

If you wish to shift more than one bit per scan, you must create a loop in
your application using the JMP, LBL, and CTU instructions.
This instruction uses the following operands:
• File - The file operand is the address of the bit array that is to be
manipulated.
• Control - The control operand is the address of the BSL's control
element. The control element consists of 3 words:
15 14 13
Word 0 EN (1) --
DN
Word 1 Size of bit array (number of bits).
Word 2 not used
(1) EN - Enable Bit is set on false-to-true transition of the rung and indicates the instruction is enabled.
(2) DN - Done Bit, when set, indicates that the bit array has shifted one position.
(3) ER - Error Bit, when set, indicates that the instruction detected an error such as entering a negative number for the
length or source operand.
(4) UL - Unload Bit is the instruction's output. Avoid using the UL (unload) bit when the ER (error) bit is set.
• Bit Address - The source is the address of the bit to be transferred into
the bit array at the first (lowest) bit position.
• Length - The length operand contains the length of the bit array in
bits. The valid data range for length is from 0 to 2048.
Addressing Modes and File Types can be used as shown in the following
table:
Table 14.7 BSL Instruction Valid Addressing Modes and File Types
For definitions of the terms used in this table see Using the Instruction Descriptions on page4-2.
Data Files
Parameter
File • • •
(2)
Control
Length
Source • • • • •
(1) See Important note about indirect addressing.
(2) Control file only. Not valid for Timers and Counters.
You cannot use indirect addressing with: S, ST, MG, PD,
IMPORTANT
RTC, HSC, PTO, PWM, STI, EII, BHI, MMI, DATI, TPI, CS,
IOS, and DLS files.
12 11 10 9 8 7 6 5 4 3 2 1 0
(2) -- (3) (4) not used
ER UL
Function Files
• •
•
File Instructions 14-5
Address
Address
(1)
Level
Mode
• • • •
• •
• •
• • •
Publication 1762-RM001C-EN-P