1 Publication 1762-RM001C-EN-P
Chapter
7
Relay-Type (Bit) Instructions
Use relay-type (bit) instructions to monitor and/or control bits in a data
file or function file, such as input bits or timer control-word bits. The
following instructions are described in this chapter:
These instructions operate on a single bit of data. During operation, the
processor may set or reset the bit, based on logical continuity of ladder
rungs. You can address a bit as many times as your program requires.
XIC - Examine if Closed
XIO - Examine if Open
Instruction Type: input
Use the XIC instruction to determine if the addressed bit is on. Use the
XIO instruction to determine if the addressed bit is off.
When used on a rung, the bit address being examined can correspond to
the status of real world input devices connected to the base unit or
Instruction Used To: Page
XIC - Examine if Closed Examine a bit for an ON condition 7-1
XIO - Examine if Open Examine a bit for an OFF condition 7-1
OTE - Output Enable Turn ON or OFF a bit (non-retentive) 7-3
OTL - Output Latch Latch a bit ON (retentive) 7-4
OTU - Output Unlatch Unlatch a bit OFF (retentive) 7-4
ONS - One Shot Detect an OFF to ON transition 7-5
OSR - One Shot Rising Detect an OFF to ON transition 7-6
OSF - One Shot Falling Detect an ON to OFF transition 7-6
B3:0
0
B3:0
0
Table 7.1 Execution Time for the XIC and XIO Instructions
Controller When Instruction Is:
True False
MicroLogix 1200 0.9
µ
s0.8
µ
s
MicroLogix 1500 0.9
µ
s0.7
µ
s
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