Rockwell Automation 1761-HHP-B30 MicroLogix 1000 with Hand-Held Programmer (HHP) - Manual (Page 126)

Chapter 8
Using Basic Instructions
8–7
The OSR instruction is a retentive input instruction that triggers an event to
occur one time. Use the OSR instruction when an event must start based on
the change of state of the rung from false to true.
When the rung conditions preceding the OSR instruction go from false to
true, the OSR instruction becomes true for one scan. After one scan is
complete, the OSR instruction becomes false, even if the rung conditions
preceding it remain true. The OSR instruction only becomes true again if the
rung conditions preceding it transition from false to true.
The controller allows you to use one OSR instruction per output in a rung.
Entering Parameters
The address assigned to the OSR instruction is not the one-shot address
referenced by your program, nor does it indicate the state of the OSR
instruction. This address allows the OSR instruction to remember its
previous rung state.
Use a bit address from either the bit or integer data file. The addressed bit is
set (1) as long as rung conditions preceding the OSR instruction are true
(even if the OSR instruction has become false); the bit is reset (0) when rung
conditions preceding the OSR instruction are false.
Important: The bit address you use for this instruction must be unique. Do
not use it elsewhere in the program.
Do not use an input or output address to program the address
parameter of the OSR instruction.
Entering the Instruction
Mnemonic HHP Display
Function
Code
Use This Instruction When the Input:
LD OSR OSR 28 appears first on a rung or block
AND OSR OSR 29 is placed in series with any previous input
instruction in the current rung or block
You enter the instruction from within the program monitor functional area.
The example below shows how to access the LD OSR instruction. Use the
same procedure to access the AND OSR instruction, only substitute the
function code with the one provided in the table above.
P 0 0 0 O S R
B / 0 0
False
13.02
True
11.48 LD OSR
13.42 11.88 AND OSR
[OSR]
B3
0
Execution Times (
µ
sec) when:
Ladder representation:
One-Shot Rising (OSR)
8 2
L
To enter the function code, press:
FUN ENT