Provision Of I/O Signals, Process Image - Siemens SINUMERIK 880 SW 6 Planning Manual

01.93
1.3.3

Provision of I/O signals, process image

Acquisition of signals, I/O area 0 - 159
I/O signals (input/output signals) are acquired and switched by I/O modules. The I/O modules
can be located in the central controller, in expansion units or at the operator panel (I/O
submodule). There are also DMP submodules for connecting machine signals.
All machine signals that can be processed by the PLC are located in the I/O area 0 .. 159
d) c)
255 . A maximum of 160
outputs can be processed by one PLC.
When an I/O address is read, the signals that are evaluated are different from those that are
switched when the same address is written.
Direct access to I/O addresses has certain disadvantages, however, if individual signals are to
be processed; bit-oriented operations cannot be executed in the I/O area. The I/O area is
divided into two parts.
I/O devices with process image
The I/O area 0 - 127 is provided for digital individual signals or signal groups for bit-by-bit
processing. These I/O devices are depicted in the I/O area (process image). The image of the
signals in the I/O area can (and should) be processed with bit orientation.
Example:
A I 10.0
S Q 53.6
I/O devices without process image
c)
The I/O area 128 - 159 or 255
no process image for these I/Os. The signals are read and switched through directly in bytes
or words.
Example:
L PY 128 Read input signals 128.0 to 128.7
T PY 128 Switch output signals 128.0 to 128.7
–––––––
1) If using a SIMATIC S5-155U, refer to SINUMERIK 880 with S5-155U, Difference Description to PLC 135 WB in
this context
c) up to and including software version 6
d) with GA2, software version 1 and higher
© Siemens AG 1991 All Rights Reserved
SINUMERIK 880 (PJ)
c) d)
or 255
d) c)
or 256 x 8 = 1280 or 2048
d)
is provided for byte or word-oriented I/O devices. There is
6ZB5 410-0HE02
1 General Overview
1.3.3 Provision of I/O signals, process image
1)
d) c)
inputs and 1280 or 2048
c)
or
d)
1–21