Basic Instructions; Bit Logic Operations; Bit Logic Instructions - Siemens S7-1200 System Manual
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Also See for S7-1200:
- Operating instructions manual (132 pages) ,
- Programming manualline (74 pages) ,
- Manual (46 pages)
Table of Contents
Basic instructions
7.1
Bit logic operations
7.1.1
Bit logic instructions
LAD and FBD are very effective for handling Boolean logic. While SCL is especially effective
for complex mathematical computation and for project control structures, you can use SCL
for Boolean logic.
LAD contacts
Table 7- 1
Normally open and normally closed contacts
LAD
SCL
IF in THEN
ELSE
END_IF;
IF NOT (in) THEN
ELSE
END_IF;
Table 7- 2
Data types for the parameters
Parameter
IN
● The Normally Open contact is closed (ON) when the assigned bit value is equal to 1.
● The Normally Closed contact is closed (ON) when the assigned bit value is equal to 0.
● Contacts connected in series create AND logic networks.
● Contacts connected in parallel create OR logic networks.
S7-1200 Programmable controller
System Manual, 03/2014, A5E02486680-AG
Description
Normally open and normally closed contacts: You can connect contacts
Statement;
to other contacts and create your own combination logic. If the input bit
you specify uses memory identifier I (input) or Q (output), then the bit
Statement;
value is read from the process-image register. The physical contact
signals in your control process are wired to I terminals on the PLC. The
CPU scans the wired input signals and continuously updates the
corresponding state values in the process-image input register.
Statement;
You can perform an immediate read of a physical input using ":P"
following the I offset (example: "%I3.4:P"). For an immediate read, the bit
Statement;
data values are read directly from the physical input instead of the
process image. An immediate read does not update the process image.
Data type
Bool
Description
Assigned bit
7
203
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