Configuring
7.1 Configuring the CPU
Automation system
170
System Manual, 12/2017, A5E03461182-AE
Value status
The value status is additional binary information of a digital input or output signal. It is
entered simultaneously with the process signal in the process image input and provides
information about the validity of the input or output signal.
If you enable the value status for a digital module, then additional bytes are allocated in the
input address area. Each bit in the value status is assigned to a channel and provides
information about the validity of the process value. You can find the assignment in the
product manual for the respective I/O module.
The value status is influenced by all diagnostics that might falsify the process value, e.g. wire
break, short-circuit.
●
1
B
: A valid process value is being output or read for the channel.
●
0
B
: A substitute value is being output for the channel, or the channel is deactivated, faulty
or inaccessible.
You can find additional information on evaluation and processing of the value status for fail-
safe digital modules in the SIMATIC Safety – Configuring and Programming
http://support.automation.siemens.com/WW/view/en/54110126
) manual.
Reference
Additional information on addressing and address allocation with value status can be found
in the manuals of the digital modules, and in the online help for STEP 7. An example of the
evaluation of the value status in the user program is available in the function manual
Diagnostics (
http://support.automation.siemens.com/WW/view/en/59192926
).
7.1.2.3
Addressing analog modules
Introduction
The following section describes the addressing of the analog modules. In your user program,
you require the addresses of the channels of the analog module.
Analog module addresses
The address of an analog channel is always a word address. The channel address depends
on the module start address. STEP 7 automatically assigns the channel addresses during
configuration. Based on the module start addresses, STEP 7 assigns the channel addresses
in increasing sequence (in the following figure, the module start address is 256).
When you insert an analog module into a free slot, STEP 7 assigns a default address. You
can change the assigned default address in STEP 7.
Содержание Simatic S7-1500/ET 200MP
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