Addressing
S5-95F
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.
Figure 6-8. Loading the Signal States of the Onboard Inputs and Outputs
A I
x.x
L IB x
L IW x
L PY x
L PW x
PII
T PY x
T PW x
= Q x.x
T QB x
T QW x
Access through the process
image I/O tables
Direct Access
Byte addresses of the onboard inputs
Byte addresses of the onboard outputs
Access through the process
image I/O tables
Direct Access
PIQ
Control program
6-12
EWA 4NEB 812 6210-02
