Siemens SPC3 - Manual (Page 9)

SPC3 PROFIBUS Interface Center
SPC3 Hardware Description V1.3 Page 7
Copyright (C) Siemens AG 2003 All rights reserved. 2003/04
1 Introduction
For simple and fast digital exchange between programmable logic controllers, Siemens offers its users
several ASICs. These ASICs are based on and are completely handled on the principles of the EN 50170
Vol. 2, of data traffic between individual programmable logic controller stations.
The following ASICs are available to support intelligent slave solutions, that is, implementations with a
microprocessor.
The ASPC2 already has integrated many parts of Layer 2, but the ASPC2 also requires a processor’s
support. This ASIC supports baud rates up to 12 Mbaud. In its complexity, this ASIC is conceived primarily
for master applications.
Due to the integration of the complete PROFIBUS-DP protocol, the SPC3 decisively relieves the processor
of an intelligent PROFIBUS slave. The SPC3 can be operated on the bus with a baud rate of up to 12
MBaud.
However, there are also simple devices in the automation engineering area, such as switches and
thermoelements, that do not require a microprocessor to record their states.
There are two additional ASICs available with the designations SPM2 (Siemens Profibus Multiplexer,
Version 2 ) and LSPM2 (Lean Siemens PROFIBUS Multiplexer) for an economical adaptation of these
devices. These blocks work as a DP slave in the bus system (according to DIN E 19245 T3) and work with
baud rates up to 12 Mbaud. A master addresses these blocks by means of Layer 2 of the 7 layer model.
After these blocks have received an error-free telegram, they independently generate the required response
telegrams.
The LSPM2 has the same functions as the SPM2, but the LSPM2 has a decreased number of I/O ports and
diagnostics ports.