Siemens appendix AS 235 H automation system, design

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Automation systems

AS 235 H

Basic cabinet

Partial system I Partial system II

SV	Backup module	SV
	DC 24 V

N-AS

AMD

BK2

EAB2

BK1

EAB1

CPU

RAM

BAB/DG

SB

VKB

SB

BAB/DG

RAM

CPU

BK2

EAB2

BK1

EAB1

AMD

N-AS

AS 235 H basic unit

ML ML ML VD VD

A

utomatic circuit-breakers

ST1

1

2

3

1

2

GE

AS 235 H

EE1

EE2

EAVU

EE3

SES

EE4

EE5

EAVU

EE6

EE7

			V1	V2	ST2	AV	UI	UI	BT
							Bus A	Bus B
		Power supply subrack
AMD	Interface module for mini floppy disk unit
AV	Connection distributor for 20-m local bus
BAB	Bus terminator module
BK	Interface module for operation channel
BT	Flashing pulse generator
CPU	Central processor module
DG	Diagnostics interface
EAB	Interface module for I/O bus
EAVU	I/O bus comparator and switchover module
EE	Extension unit
GE	Basic unit

Fig. 3/5 AS 235 H automation system, design

The memory module with Error Detection and Correction EDC can correct a 1-bit error when reading, and eliminate it in the memory cell together with the system software.

The interface module for I/O bus establishes the connection between the 8-bit central bus and the I/O bus. One or two of these modules can be plugged into the basic unit of each partial system of the AS 235 H system:

•The interface module for I/O bus 1 (A) is essential for partial systems I and II and is included in the delivery of the basic unit. Each of the two CPUs operating with synchronous clocks is connected to the I/O bus comparator and switchover modules (EAVU) of the basic cabinet via its own interface module and own I/O bus 1 (A). Both the two interface modules and the two I/O buses 1 (A) are redundant to one another. This enables two-channel, clock-synchronous triggering of the EAVU mod- ules.

•The interface modules for I/O bus 2 (B) must be ordered addi- tionally (one module for each partial system). The interface modules are only required if an extension cabinet is used in addition to the basic cabinet.

AS 235 H basic unit AS 235 H extension cabinet

ML	Alarm logic module
N-AS	Interface module for 20-m local bus
RAM	Memory module
SB	Synchronization module
SES	Power supply subrack
ST	24 V sockets for connection of keyboards
SV	Power supply module DC 24 V / DC 5 V
UI	Bus converter

VSupply diode

VD	Diode module for linking signals
VKB	Comparator/coupling module

Each of the two partial systems has a synchronization module. The two modules are redundant to one another and linked together without feedback. Together with the comparator/cou- pling module they constitute the central components of the AS 235 H system responsible for the control, coordination and monitoring of the two partial systems. The synchronization mod- ule is also required for operation of a non-redundant basic unit.

Depending on the configuration of the automation system, the power supply subrack is equipped with one or more alarm logic modules:

•Alarm logic module ML1 (basic cabinet with 1 partial system)

•Alarm logic modules ML1 and ML2 (basic cabinet with 2 redundant partial systems)

•Alarm logic modules ML1, ML2 and ML3 (basic cabinet with 2 redundant partial systems and extension cabinet).

The alarm logic models monitor the central processing units and the optionally used signal inputs for temperature monitoring, door contact, fan contact and spare contact. In the event of a fault, the cabinet lamps on the basic and extension cabinets are triggered via these contacts.

3/10 Siemens PLT 111 · 1999