Siemens SIMATIC PC RI25/45 Parts list manual

Contents
System Unit 1
Motherboard 2
Bus Board 3
Monitoring Module 4
Hard Disk Drive 5
Floppy Disk Drive 6
CD-ROM Drive 7
Back-Up Battery 8
220 V Power Supply 9
Index
C79000-G7076-C808-01
SIMATIC PC RI25/45
SIMATIC
Technical Description

Thismanualcontainsnoticeswhichyoushouldobservetoensureyourownpersonalsafety,as well as
toprotecttheproductandconnectedequipment.Thesenoticesarehighlightedinthemanualbya
warningtriangleandaremarkedasfollows accordingtothelevelofdanger:
!Danger
indicatesthatdeath,severepersonalinjuryorsubstantialpropertydamagewillresultifproperprecautions
arenottaken.
!Warning
indicatesthatdeath,severepersonalinjuryorsubstantialpropertydamagecanresultifproperprecau-
tionsarenottaken.
!Caution
indicatesthatminorpersonalinjuryorpropertydamagecanresultifproperprecautionsarenottaken.
Note
drawsyourattentiontoparticularlyimportantinformationontheproduct,handlingtheproduct,ortoa
particularpartofthedocumentation.
Thedevice/systemmayonlybesetupandoperatedinconjunctionwiththismanual.
Onlyqualifiedpersonnel should be allowedtoinstalland work onthisequipment.Qualified persons
aredefinedaspersonswhoareauthorizedtocommission,toground,andtotagcircuits,equipment,
andsystemsinaccordancewithestablishedsafetypracticesandstandards.
Note the following:
!Warning
Thisdeviceanditscomponentsmayonly beused for theapplications described inthe catalog orthe
technicaldescription,andonlyinconnectionwithdevicesorcomponentsfromothermanufacturers
whichhavebeenapprovedorrecommendedbySiemens.
Thisproductcanonlyfunctioncorrectlyandsafelyifitistransported,stored,setup,andinstalled
correctly,andoperatedandmaintainedasrecommended.
SIMATICR,SIMATICNETRandSINECRareregisteredtrademarksofSIEMENSAG.
Third parties using for their own purposes any other names in this document which refer to
trademarks might infringe upon the rights of the trademark owners.
We have checked the contents of this manual for agreement with the
hardwareandsoftwaredescribed.Sincedeviationscannotbeprecluded
entirely, we cannot guarantee full agreement. However, the data in this
manualarereviewedregularlyandanynecessarycorrectionsincludedin
subsequenteditions.Suggestionsforimprovementarewelcomed.
Subject to change without prior notice
ESiemensAG 1998
Disclaimer of LiabilityCopyrightESiemensAG 1998 All rights reserved
Thereproduction,transmissionoruseofthisdocumentoritscontentsis
notpermittedwithoutexpresswrittenauthority.Offenderswillbeliablefor
damages.Allrights,includingrightscreatedbypatentgrantorregistration
ofautilitymodel or design,are reserved.
Siemens AG
Bereich Automatisierungs- und Antriebstechnik
Geschaeftsgebiet Industrie-Automatisierungssysteme
Postfach 4848, D-90327Nuernberg
SiemensAktiengesellschaft C79000-G7076-C808
Safety Guidelines
Qualified Personnel
Correct Usage
Trademarks

iii
SIMATIC PC RI25/45, TechnicalDescription
C79000-G7076-C808-01
Contents
1 System Unit 1-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.1 Dimensions of Expansion Modules 1-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.2 Power Requirements of the Components (Maximum Values) 1-4. . . . . . . . . .
1.3 Removing and Installing Components 1-5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.3.1 Changing the Air Filter 1-7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.3.2 Removing the Protective Sliding Cover 1-7. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.3.3 Opening the System Unit 1-8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.3.4 Removing and Installing Fans 1-9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.3.5 Removing and Installing the 3.5” Floppy Disk Drive 1-10. . . . . . . . . . . . . . . . . .
1.3.6 Removing and Installing the Drive Block (Front) 1-11. . . . . . . . . . . . . . . . . . . . .
1.3.7 Removing and Installing Hard Disk Drives (Back) 1-12. . . . . . . . . . . . . . . . . . . .
1.3.8 Removing and Installing the Display Board 1-13. . . . . . . . . . . . . . . . . . . . . . . . . .
1.3.9 Removing and Installing Module Retainers (only RI45/RI45PCS) 1-14. . . . . . .
1.3.10 Removing and Installing Expansion Modules 1-15. . . . . . . . . . . . . . . . . . . . . . . .
1.3.11 Removing and Installing the Bus Board 1-15. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.3.12 Removing and Installing the CPU Board 1-16. . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.3.13 Connecting the Multipoint Interface (MPI/DP) 1-17. . . . . . . . . . . . . . . . . . . . . . .
1.4 Error Diagnostics 1-18. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2 Motherboard 2-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.1 Components 2-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.2 Processor 2-3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.3 Cache Modules 2-4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.4 Graphics Interface Module 2-5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.5 Memory 2-8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.6 Changing the Backup Battery 2-11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.7 Block Diagram of the Motherboard 2-12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.8 Hardware Ports 2-13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.9 Hardware Addresses 2-26. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.10 Interrupt and DMA Assignments 2-30. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.11 Setup 2-31. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.11.1 Main Menu 2-35. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.11.2 Advanced Menu 2-44. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.11.3 Security Menu 2-46. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.11.4 Power Menu 2-47. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.11.5 Exit Menu 2-49. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.12 Diagnostic Messages (Port 80) 2-51. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

iv SIMATIC PC RI25/45, TechnicalDescription
C79000-G7076-C808-01
3 Bus Board/Operator Panel 3-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.1 Technical Specifications 3-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.2 Installation and Functional Specifications 3-2. . . . . . . . . . . . . . . . . . . . . . . . . . .
3.2.1 Power Supply Connection 3-3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.2.2 Power-Good-Signal 3-5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.2.3 Fan Connector P405, P407 3-6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.2.4 IDSEL Setting for PCI Slots 3-6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.3 Operator Panel 3-7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.4 Operator Panel for SafeCard 3-8. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4 Monitoring Module 4-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.1 Overview 4-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.2 Status and Diagnostic Displays 4-5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.3 Temperature Monitoring / Display and Fan Control 4-6. . . . . . . . . . . . . . . . . . .
4.4 Watchdog (WD) 4-7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.5 Relay Output 4-9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.6 Battery-Backed RAM (optional) 4-10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.7 Software Interfaces 4-11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4.8 Hardware Ports 4-14. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5 Hard Disk Drive 5-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.1 Technical Specifications 5-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6 Floppy Disk Drive 6-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6.1 Technical Specifications 6-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7 CD-ROM Drive 7-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.1 CD-ROM Drive 7-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8 Back-Up Battery 8-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8.1 Back-Up Battery 8-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9 220 V Power Supply 9-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.1 Technical Specifications 9-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Index Index-1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Contents

1-1
SIMATIC PC RI25/45, TechnicalDescription
C79000-G7076-C808-01
System Unit
Section Description Page
1.1 Dimensions of Expansion Modules 1-2
1.2 Power Requirements of the Components (Maximum
Values) 1-4
1.3 Removing and Installing Components 1-5
1.3.1 Changing the Air Filter 1-7
1.3.2 Removing the Protective Sliding Cover 1-7
1.3.3 Opening the System Unit 1-8
1.3.4 Removing and Installing Fans 1-9
1.3.5 Removing and Installing the 3.5” Floppy Disk Drive 1-10
1.3.6 Removing and Installing the Drive Block (Front) 1-11
1.3.7 Removing and Installing Hard Disk Drives (Back) 1-12
1.3.8 Removing and Installing the Display Board 1-13
1.3.9 Removing and Installing Module Retainers (only
RI45/RI45PCS) 1-14
1.3.10 Removing and Installing Expansion Modules 1-15
1.3.11 Removing and Installing the Bus Board 1-15
1.3.12 Removing and Installing the CPU Board 1-16
1.3.13 Connecting the Multipoint Interface (MPI/DP) 1-17
1.4 Error Diagnostics 1-18
Chapter
Overview
1

1-2 SIMATIC PC RI25/45, TechnicalDescription
C79000-G7076-C808-01
1.1 Dimensions of Expansion Modules
The SIMATIC PC RI25/45 is designed for modules according to AT/PCI
specifications. The size of the modules should not exceed the dimensions
indicated. If the given height is exceeded, this may cause contacting
problems, functional disorders or difficulties with installation. The figures
below illustrate two cards with full AT/PCI overall length. Individual slots
may require different card dimensions.
340.7
106.7
A31 A1
(All dimensions in mm)
Figure 1-1 XT module
340.7
121.92
A31 A1
(All dimensions in mm)
C18 C1
Figure 1-2 AT module
Information on
Modules
System Unit

1-3
SIMATIC PC RI25/45, TechnicalDescription
C79000-G7076-C808-01
174.63
106.68
8.19
(All dimensions in mm)
Figure 1-3 Small PCI module (5 V)
312
106.68
8.19
(All dimensions in mm)
Figure 1-4 Large PCI module (5 V)
Large PCI modules have to be equipped with a so-called extender (usually
included with large PCI modules) which serves to guide them along the rails
of the ventilator case. The extender guides large PCI modules along the rails
of ISA modules.
Information on
Large PCI Modules
System Unit

1-4 SIMATIC PC RI25/45, TechnicalDescription
C79000-G7076-C808-01
1.2 Power Requirements of the Components (Maximum Values)
Component + 5V – 5V + 12V – 12V
Motherboard 5.1 A 0.01 A 0.1 A 0.02 A
SafeCard monitoring module 0.35 A –0.03A –
Front fan 0.5 A
3.5” floppy disk drive *)
Hard disk *)
*) see Section 5.1
Due to thermal stress, the maximum capacity of the power supply is
restricted to:
Power supply Restriction
Standard power supply (220 V) maximum load 160 W
Basic System
Restrictions on
Power Supply
System Unit

1-5
SIMATIC PC RI25/45, TechnicalDescription
C79000-G7076-C808-01
1.3 Removing and Installing Components
The system unit is designed to enable any necessary maintenance work to be
carried out quickly and at low cost.
!Warning
Please read the warnings at the front of the User’s Guide before you open the
housing of the system unit.
Do not open the housing unless you need to install or remove
components, or to replace the battery.
Write down your configuration parameters.
Disconnect the unit from the power supply by unplugging the power plug.
!Caution
Risk of damage to the unit!
Note that only qualified personnel should be allowed to work on the open unit,
so the warranty on the device is not affected. Authorized Siemens maintenance
and repair centers offer you a specialist maintenance service. The User’sGuide
contains the addresses.
!Caution
The electronic components of the printed boards are extremely sensitive to
electrostatic discharge. When handling the boards, you must follow the
guidelines for electrostatically sensitive components (ESD guidelines) at the
end of this manual.
All technical specifications and licenses apply only to expansion functions
approved by SIEMENS. No liability can be assumed for functional
constraints caused by the use of devices and components of other
manufacturers.
All modules and components in the PC are electrostatically sensitive. Please
read the ESD guidelines. The following sign warns that electrostatically
sensitive modules are present.
Prerequisites
Limitation of
Liability
System Unit

1-6 SIMATIC PC RI25/45, TechnicalDescription
C79000-G7076-C808-01
The following rules are mandatory when carrying out any work on the open
unit, and should be read carefully before opening the unit:
Before you disconnect the power supply cable, discharge any electrostatic
charge on your body. You can do this by touching metallic parts, such as
screws, on the rear panel of the PC.
Discharge any electrostatic charge from tools that you are using.
Wear a grounding wrist strap if you are handling components.
Leave components and modules in their packing until you are ready to
install them.
Disconnect the PC from its power supply before plugging in or removing
any modules or components.
Touch components and modules only on their edges. Above all, do not
touch the connecting pins and printed conductors.
Do not operate the PC with the cover open.
Use a suitable Philips or Torx screwdriver to remove or install components.
Before Opening
the Unit
Tools
System Unit

1-7
SIMATIC PC RI25/45, TechnicalDescription
C79000-G7076-C808-01
1.3.1 Changing the Air Filter
Note the following steps while replacing the air filter:
The protective cover has to be locked completely (snapped in place on the
right side).
The fan cover can be lifted off (there is no need to remove the cover of the
system unit); it is simply snapped in place.
The air filter is not attached to anything and can easily be removed.
Operator panel
Status display
LEDs
Reset key
Lock
Fan cover
Figure 1-5 BedienelementedesSIMATIC PC RI
The protective grid can also be removed, but you will have to use a little
force. Since the filter is replaced while the PC is operating, the protective
grid protects you from injuring yourself on the sharp edges of the fan and
prevents the filter pad from being sucked into the fan.
!Caution
When the fans are operating, particles can be drawn into the system unit.
The protective grid may only be removed with the PC switched off.
1.3.2 Removing the Protective Sliding Cover
Please note the following if the protective cover has to be removed:
When the fan cover is in place, the protective cover can only be moved to
the left as far as it will go. In this position, in case you forgot to move the
protective sliding cover back, a limited amount of air can still be drawn in.
If you first removed the fan cover you can slide the cover completely off its
guides.
If the protective sliding cover is completely closed (all the way to the right),
access to drives can be prevented.
Important
Information
Notes
System Unit

1-8 SIMATIC PC RI25/45, TechnicalDescription
C79000-G7076-C808-01
1.3.3 Opening the System Unit
Figure 1-6 illustrates the arrangement of units in the open housing of the system
unit:
– motherboard together with with bus module
– SafeCard monitoring module (optional)
– 3.5” floppy disk drive and hard disk drive
– power supply
– fan cage with two fans
Two fans 3.5” floppy disk drive
Rearsupport for
hard disk drives
(onlywith RI45)
Busboard
Fancage
SafeCard
Front drive block
Representedwithoutcrossbeamwithretainers
Motherboard
Powersupply
Figure 1-6 SIMATIC PC RI
First remove the screws at the top. Hold the cover at its front left and right
edges, lift it up and off by sliding it back a little.
Overview of the
Functional Units
Opening the
System Unit
System Unit

1-9
SIMATIC PC RI25/45, TechnicalDescription
C79000-G7076-C808-01
1.3.4 Removing and Installing Fans
Proceed as follows to remove or install the fan:
Disconnect the cables from the monitoring module, the motherboard,and the
bus module and write down their previous connections.
Provided expansion modules are not installed or have previously been
removed, the fan cage can be taken out. First remove the two clamps of the
fan cage (see Figure 1-7) then push the top of the two side sections outward
and lift the fan cage up.
First the connecting cables have to be carefully removed from the bottom of
the cut-out, then remove the two fans.
If expansion modules are installed, you can take out the fans from the fan
cage, even without previously removing the expansion modules: first unplug
the connecting cable from the fan, then push the hook slightly backwards
(use a screwdriver), and lift up the fan.
Proceed in reverse order to install the fans.
Clamps
Figure 1-7 Removing the fan cage
Procedure
System Unit

1-10 SIMATIC PC RI25/45, TechnicalDescription
C79000-G7076-C808-01
1.3.5 Removing and Installing the 3.5” Floppy Disk Drive
Proceed as follows to replace the floppy disk drive:
Disconnect all the cables and write down their prevoius connections.
Release the two screws at the top of the drive support (see arrows in
Figure 1-8) and pull out the drive from the back.
Mountingscrews
Figure 1-8 Removing the floppy disk drive
Proceed in reverse order to install a floppy disk drive.
Procedure
System Unit

1-11
SIMATIC PC RI25/45, TechnicalDescription
C79000-G7076-C808-01
1.3.6 Removing and Installing the Drive Block (Front)
Proceed as follows to replace the drive block:
Release the screw on the bottom of the housing (do not unscrew it
completely).
Mountingscrew
Figure 1-9 Mounting the front drive block
First pull the drive block two centimeters (0.8 inches) to the rear (see
direction of arrow in Figure 1-9) then pull the front block out of the housing.
To replace the drive, or to install a second drive (for example, a CD-ROM
drive), release the two upper and the two lower screws.
Then remove the 3.5” support which lodges the hard disk drive and release
the four screws which connect hard disk drive and support.
5.25” drives or CD-ROM drives do not require any support.
To install the drive block, proceed in reverse order .
Procedure
System Unit

1-12 SIMATIC PC RI25/45, TechnicalDescription
C79000-G7076-C808-01
1.3.7 Removing and Installing Hard Disk Drives (Back)
Proceed as follows to replace or install hard drives:
You can install up to two additional hard disk drives in the support located
at the back of your PC.
The support is mounted with three screws (see Figure 1-10). Two of them are
directly accessible at the back of the system unit. The third screw can only
be reached inside the unit from the top. The hard disk drives must be fixed
with screws at the upper and lower end of the support.
Then connect the installed hard disk drives, CPU board and power supply
by plugging in the corresponding connecting cables.
Mountingscrews
Figure 1-10 Removing and installing hard disk drives
Procedure
System Unit

1-13
SIMATIC PC RI25/45, TechnicalDescription
C79000-G7076-C808-01
1.3.8 Removing and Installing the Display Board
First disconnect the cables and write down the previous connections.
Then pry the display board out of the catches (see Figure 1-11).
Catches
Figure 1-11 Removing the display board
After unscrewing (two hexagonal socket screws) the right handle and the
front plate, the panel covering can be taken off.
System Unit

1-14 SIMATIC PC RI25/45, TechnicalDescription
C79000-G7076-C808-01
1.3.9 Removing and Installing Module Retainers (only RI45/RI45PCS)
First remove the crossbeam on which the modules are mounted.
Bend the two notched spring clips slightly inwards to release the snap-in
lockings.
Grip the crossbeam and push it about 1 centimeter (half an inch)
backward and then lift it out with the retainers.
Retainer
Figure 1-12 Moduleretainersand crossbeam
Proceed in reverse order to install the retainers.
Adjusting retainers:
Insert the sliding element at the top and push it down until it covers the
module. Then guide the module into the notch.
!Caution
Do not exert pressure on the module. This means that you should not push
down or force the retainers in any way.
Cut off the part of the sliding element that sticks out as described below:
– Scratch a notch in the top of the sliding element on the upper edge of
the retainer using a knife and bend it over to break it off.
– Cut off any leftover part using a sharp side cutter or a hacksaw.
System Unit

1-15
SIMATIC PC RI25/45, TechnicalDescription
C79000-G7076-C808-01
1.3.10 Removing and Installing Expansion Modules
Disconnect all connectors. Write down previous connections.
Release the screw which mounts the modules on the back of the system
unit.
Carefully remove the module without bending it.
To install the new module, proceed in reverse order.
1.3.11 Removing and Installing the Bus Board
First remove all expansion modules.
Disconnect all connectiong cables or connectors and write down their
previous connections.
Release 5 screws (2 at the front with the spacer between the CPU board
and 3 screws at the back).
Lift the bus board out of the connector to the CPU board.
To install a new board, proceed in reverse order.
System Unit

1-16 SIMATIC PC RI25/45, TechnicalDescription
C79000-G7076-C808-01
1.3.12 Removing and Installing the CPU Board
Remove module supports (only RI45/RI45PCS)
Remove all expansion modules and slot plates.
Disconnect all cables from the CPU board and the bus board and write
down their previous connections.
Release the 2 screws at the back of the system unit (see arrows in
Figure 1-13), then push forward the CPU board and its baseplate until it
comes to a stop and lift it out. You can now remove the bus board if
necessary.
Mountingscrews
Figure 1-13 Removing the CPU board
To install the board, follow the instructions in reverse order.
The bus board and supporting plate are not included with the CPU board
when supplied as a spare part.
System Unit