Blocks and Their Functions
S5-95F
9.2.5
Analog Value Conditioning Blocks - FB250 and FB251 -
Function block FB250 reads in an analog value from an analog input module and outputs a value XA
in the scale range specified by the user.
Function block FB251 allows you to output analog values to analog output modules. Values from the
range between the "UGR" (lower limit) parameters and the "OGR" (upper limit) parameters are
converted to the nominal range of the selected module.
You will find more information on the following topics in section 11.6:
•
Calling up and setting parameters in FB250
•
Calling up and setting parameters in FB251
•
An example of analog value processing with FB250 and FB251.
9.2.6
Additional Calling Up of Test Routines - FB252 -
The operating system tests all safety-relevant system components at least once per hour (see
Chapter 2). In the following section, this test is also called background test. If your automated
process requires shorter test intervals for particular system components or if you wish to determine
the instant of a test yourself, then you use FB252 to execute additional tests. The test routines are
executed immediately after the FB252 is called up. You call up FB252 only in the cyclic program
(OB1).
Figure 9-5. List of S5-95F Self-Test Components
Load voltage
failure routine
Logical program counter
CPU
Operating system
comparison
RAM with STEP 5 objects
Onboard DI
Onboard DQ
Onboard interrupt DI
Onboard counters
External DI
External DQ
Processor RAM
Memory submodule
Power failure
routine
Scan time monitor
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