Siemens SIMATIC S7-200 System Manual page 478

S7-200 Programmable Controller System Manual
Operation
In the process image of the S7-200, the AS--Interface Module occupies a digital input byte (status
byte), a digital output byte (control byte), 8 analog input and 8 analog output words. The
AS--Interface Module uses two logical module positions. You can use the status and the control
byte to set the mode of the AS--Interface Module using a user program. Depending on its mode,
the AS--Interface stores either the I/O data of the AS--Interface slave, diagnostics values, or
enables master calls (for example, changing a slave address) in the analog address area of the
S7-200.
All the connected AS--Interface slaves can be configured at the touch of a button. Further
configuration of the CP is not necessary.
Caution
When you use the AS--Interface Module, you must disable analog filtering in the CPU.
If analog filtering is not disabled in the CPU, the digital point data will be destroyed, and error
conditions will not be returned as bit values in the analog word.
Ensure that analog filtering in the CPU is disabled.
Functions
The CP 243--2 is the AS--Interface master for the M1e master class, which means that it supports
all the specified functions. This makes it possible to operate up to 31 digital slaves on the
AS--Interface by means of double address assignment (A--B). The CP 243--2 can be set to two
different modes:
Standard mode: access to the I/O data
-
of the AS--Interface slave
Extended mode: master calls (for
-
example, write parameters) or
diagnostic value request
Connections
The AS--Interface Module has the following
connections:
Two connections to the AS--Interface
-
Module cable (bridged internally)
One connection for functional ground
-
The terminals are located under the cover of
the front panel as shown in Figure A-42. h f l
Caution
The load capacity of the AS--Interface Module contacts is a maximum of 3 A. If this value is
exceeded on the AS--Interface Module cable, the AS--Interface must not be looped into the AS--I
cable, but must be connected by a separate cable (in this case, only one pair of terminals of the
AS--Interface Module is used). The AS--Interface must be connected to the grounding conductor
via the ground terminal.
Tip
The AS--Interface Module has a connection for functional ground. This connector should be
connected to the PE conductor with as little resistance as possible.
Additional Information
For more information about the CP 243--2 AS--Interface Master, refer to the SIMATIC NET CP
243- -2 AS-Interface Master manual.
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h i Fi A
+ - -
AS- -I Cables
Figure A-42 Connecting the AS- -Interface Module
Cable
Functional Ground
+ - -