Direct Access To Onboard I/Os - Siemens SIMATIC S5-95F Manual

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Addressing
6.6.3

Direct Access to Onboard I/Os

Direct access makes it possible for you to exchange information in the interrupt OBs with the I/Os
without having to read/write the information from/to the PIQ or PII first. To a degree, you circumvent
the PII or PIQ and directly exchange information with the inputs or outputs.
You have direct access to all of the onboard I/Os. Using the "L PB/PYxx" or "L PWxx" statements,
you can read in (load) the signal state of an input byte or input word into the control program at any
time. You can also use the "T PB/PYxx" or "T PWxx" statements to write (transfer) output
information directly to an output byte or output word.
Access through the process
Access through the process
Figure 6-8. Loading the Signal States of the Onboard Inputs and Outputs
6-12
image I/O tables
Byte addresses of the onboard inputs
PII
A I x.x
L IB x
L IW x
Control program
= Q x.x
T QB x
T QW x
PIQ
Byte addresses of the onboard outputs
image I/O tables
Direct Access
L PY x
L PW x
T PY x
T PW x
Direct Access
S5-95F
EWA 4NEB 812 6210-02

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