Allen-Bradley MicroLogix 1200 Reference Manual page 351

Indirect Addressing
The following sections describe how indirect addressing affects the
execution time of instructions for the Micrologix 1200 controllers. The
timing for an indirect address is affected by the form of the indirect
address.
For the address forms in the following table, you can interchange the
following file types:
• Input (I) and Output (O)
• Bit (B), Integer (N)
• Timer (T), Counter (C), and Control (R)
Execution Times for the Indirect Addresses
For most types of instructions that contain an indirect address(es), look up
the form of the indirect address in the table below and add that time to
the execution time of the instruction.
[*] indicates that an indirect reference is substituted.
Table A.2 MicroLogix 1200 Instruction Execution Time Using Indirect Addressing
Address Form Operand Time (µs)
O:1.[*] 5.8
O:[*].0 15.0
O:[*].[*] 15.1
B3:[*] 5.8
B[*]:1 24.3
B[*]:[*] 24.5
L8:[*] 6.1
L[*]:1 24.4
L[*]:[*] 24.3
T4:[*] 6.0
T[*]:1 24.0
T[*]:[*] 24.2
T4:[*].ACC 6.5
T[*]:1.ACC 24.4
T[*]:[*].ACC 24.9
O:1.[*]/2 6.3
O:[*].0/2 15.2
O:[*].[*]/2 15.9
O:1.0/[*] 6.8
O:1.[*]/[*] 7.6
O:[*].0/[*] 16.6
O:[*].[*]/[*] 16.9
B3:[*]/2 6.3
B[*]:1/2 24.5
B[*]:[*]/2 25.3
MicroLogix 1200 Memory Usage and Instruction Execution Time
Address Form
B3:1/[*]
B3:[*]/[*]
B[*]:1/[*]
B[*]:[*]/[*]
L8:[*]/2
L[*]:1/2
L[*]:[*]/2
L8:1/[*]
L8:[*]/[*]
L[*]:1/[*]
L[*]:[*]/[*]
T4:[*]/DN
T[*]:1/DN
T[*]:[*]/DN
T4:[*].ACC/2
T[*]:1.ACC/2
T[*]:[*].ACC/2
T4:1/[*]
T4:[*]/[*]
T[*]:1/[*]
T[*]:[*]/[*]
T4:1.ACC/[*]
T4:[*].ACC/[*]
T[*]:1.ACC/[*]
T[*]:[*].ACC/[*]
A-5
Operand Time (µs)
6.8
7.6
25.9
26.2
6.5
24.6
25.3
6.8
7.7
26.0
25.9
6.6
24.4
24.9
7.4
24.4
25.9
6.5
8.3
26.1
26.8
6.9
8.9
26.1
27.3
Publication 1762-RM001C-EN-P