Siemens Simatic S7 Series System Manual

Program instructions
7.4 Compare
S7-200 SMART
192 System Manual, 09/2015, A5E03822230-AC
7.4
Compare
7.4.1
Compare number values
The compare instructions can compare two number values with the same data type. You can
compare bytes, integers, double integers, and real numbers.
For
LAD and FBD
: When the comparison is TRUE, the compare instruction sets ON a
contact (LAD network power flow), or output (FBD logic flow).
For
STL
: When the comparison is TRUE, the compare instructions can load, AND, or OR a 1
with the value on the top of the logic stack.
Types of comparison
Six comparison types are available:
Comparison type
The output is TRUE only if
== (LAD/FBD)
= (STL)
IN1 is equal to IN2
<> IN1 is not equal to IN2
>=
IN1 is greater than or equal to IN2
<=
IN1 is less than or equal to IN2
>
IN1 is greater than IN2
<
IN1 is less than IN2
Selecting the data types to be compared
The data type identifier that you choose determines the required data type for the IN1 and
IN2 parameters.
Data type identifier
Required IN1, IN2 data type
B
Unsigned byte
W
Signed word integer
D
Signed double word integer
R
Signed real

Siemens Simatic S7 Series Specifications

General

CPU	Varies by model (e.g., S7-300, S7-400, S7-1200, S7-1500)
Communication Interfaces	PROFIBUS, PROFINET, Ethernet, MPI
Programming	TIA Portal, STEP 7
Programming Languages	LAD, FBD, STL, SCL, GRAPH
I/O Modules	Digital, Analog, Specialty modules available
Operating Temperature	0°C to 60°C (standard models)
Mounting	DIN rail mounting
Operating Voltage	24V DC or 120/230V AC (varies by model)
Protection Class	IP20 (standard models)
Memory	Varies depending on the S7 model. Includes work memory (RAM) for program execution, load memory (EEPROM or Flash) for program storage, and system memory for operating system functions. Memory sizes range from kilobytes to megabytes.