Specifications
AS-Interface Master
Master for SIMATIC S7
CP 343-2 P
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Siemens IK PI · 2009
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Overview
The CP 343-2 P is the AS-Interface master for the SIMATIC
S7-300 PLC and the ET 200M distributed I/O device. The com-
munications processor has the following functions:
• Supports the configuration of the AS-Interface network
with STEP 7, V5.2 and later
• Up to 62 AS-Interface slaves can be connected and inte-
grated analog value transfer (according to the AS-Interface
specification V3.0)
• Supports all AS-Interface master functions in accordance with
the AS-Interface specification V3.0
• Error displays (such as AS-Interface voltage errors, configura-
tion errors) with LEDs on the front plate
• Compact enclosure in SIMATIC S7-300 design
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Benefits
• Improved plant documentation and support for servicing
thanks to documentation of the AS-Interface configuration in
the STEP 7 project
• Diagnosis of the AS-Interface network is supported
• Shorter startup times due to easy configuration at the press of
a button
• Flexible decentralized topologies can be constructed by us-
ing this communications processor in the ET 200M DP slave.
• Reduction of standstill or service times in the event of a fault
through LED displays:
- status of the AS-Interface network
- connected slaves and their operational readiness
- monitoring of the AS-Interface voltage level
• Reduced costs for spare parts inventories because the CP
can be used in both the SIMATIC S7-300 and in ET 200M.
• Ideal for complex applications through the connection option
of 62 slaves and integrated analog value processing
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Application
The CP 343-2 P is the AS-Interface master connection for
SIMATIC S7-300 and ET 200M. The connection to the AS-Inter-
face permits a maximum of 248 DI/248 DO to be accessed for
each CP.
The integrated analog value processing also enables analog
signals to be evaluated very easily (per CP max. 62 analog
slaves each with max. 4 channels or max. 2 channels in the case
of A/B analog slaves).
The CP 342-2 functionality is identical to that of the CP 343-2 P,
which means that an existing S7 user program can be used with-
out any restrictions with the new CP. The AS-Interface configura-
tion can also be downloaded/uploaded with the STEP 7 hard-
ware configuration.
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Design
The CP 343-2 P is connected to the S7-300 like an expansion
module. It features:
• Two terminals for direct connection of the AS-Interface cable
• LEDs in the frontplate for displaying the operating status and
operational readiness of all connected and activated slaves
• Pushbuttons for displaying the status information of the
slaves, for switching the operating status and entering the ex-
isting ACTUAL configuration as the SETPOINT configuration
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Function
The CP 343-2 P supports all of the specified functions of the AS-
Interface specification V3.0. This makes it possible to operate up
to 62 digital or analog slaves on the AS-Interface by means of
extended address assignment (A/B). The integrated analog
value processing allows easy access to the analog values.
The CP 343-2 P occupies 16 byte each in the I/O address space
of the SIMATIC S7-300. In this space, the digital I/O data of the
standard or A-slaves are stored. The digital I/O data of the B-
slaves and the analog I/O data can be accessed using the
S7 system functions for reading/writing data sets.
A- and B-slaves are slaves in accordance with the AS-Interface
specification V2.1 or V3.0.
If necessary, master calls can be performed using the command
interface FC ASI_3422, e.g. read/write parameter, read/write
configuration. The FC, including STEP 7 sample program, can
be downloaded from the Internet at
http://support.automation.siemens.com/WW/view/com/5581657
Configuration
All of the connected AS-Interface slaves are configured by the
press of a button. No further configuration of the CP is neces-
sary.
The CP 343-2 P also supports the configuration of the AS-
Interface network with STEP 7, V5.2. and later. The specification
of the AS-i configuration in HW-Config simplifies the setting of
slave parameters and the documentation of the plant. In partic-
ular, Siemens AS-Interface slaves can be conveniently config-
ured by means of the slave selection dialog. It is even possible
to upload the actual configuration of an AS-Interface network
that has already been set up. The stored configuration cannot
be overwritten at the touch of a button and is therefore secure
against manipulation.