Maintenance

7.1 Replacing the Backup Battery

Replacing the Backup Battery

1. Discharge any static charge by touching a grounded metal part of the S7-400.
2. Open the cover of the power supply module.
3. Using the loop(s), pull the backup battery/batteries out of the battery
compartment.

4. Insert the new backup battery/batteries in the battery compartment of the power
supply module.
Ensure correct polarity of the battery/batteries.
5. Switch on battery monitoring with the BATT INDIC slide switch.

If You ... ...Then

have a single-width power supply module, set the BATT INDIC switch to
BATT.
have a double or triple-width power supply module set the BATT INDIC switch to
and want to monitor a backup battery, 1BATT.
have a double or triple-width power supply module set the BATT INDIC switch to
and want to monitor both backup batteries, 2BATT.

6. Press the FMR button.

7. Close the cover of the power supply module.

Note
If you store the batteries for a long period, a passivation layer may form. Please
read Section 6.8, Inserting a Backup Battery.

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 Maintenance

Using Backup Batteries

You should change the backup battery once a year.
Observe the usual regulations/guidelines for disposing of lithium batteries in your
country.
Backup batteries should be stored in a cool, dry place.
Backup batteries can be stored for ten years. If they are stored for a longer period,
however, a passivation layer may form.

Rules for the Care of Backup Batteries

You must observe the following rules to avoid hazards in the care of backup
batteries:

Warning
! Risk of injury, material damage, release of hazardous substances.
Lithium batteries can explode if handled improperly. Their improper disposal may
result in the release of hazardous substances. Strictly adhere to the following in-
structions:
• Do not throw a new or low battery into an open fire and do not perform any sol-
dering work on the cell casing (max. temperature 100 °C). Do not recharge the
battery -- risk of explosion! Do not open a battery. Replace a faulty battery onoly
with the same type. Replacement batteries can be ordered from SIEMENS (for
order numbers, refer to the “Module data” reference manual, in appendix C).
This will insure that your are installing a short circuit-proof type.
• Always try to return low batteries to the manufacturer or deliver these to a regi-
stered recycling company.

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Maintenance

7.2 Replacing a Power Supply Module

Slot Numbering
If you have provided the modules in your system with slot numbering, you must
remove the number from the old module when replacing it and apply the number to
the new module.

Removing the Module (Ignore Steps 1 and 2 When Using Redundant Power
Supply Modules)
1. Set the CPU mode switch to STOP.
When you replace the power supply module in an ER, the CR may remain in the
RUN state, depending on CPU programming. You can back up the data in the
ER via the EXT. BATT. socket of the receive IM.
2. If you wish to back up the data in the CPU, you can use the EXT. BATT. socket
of the CPU (see Reference Manual, Chapter 1).
3. Set the standby switch of the power supply module to (0 V output voltages).
4. Set the line disconnector to OFF.
5. Remove the cover.
6. Remove the backup battery/batteries if applicable.
7. Disconnect the power supply connector from the power supply module.
8. Loosen the mounting screws of the module.
9. Swing the module out.

Installing a New Module

1. Check the voltage selector switch.
2. Attach the new module of the same type and swing it downwards.
3. Screw the module on.

4. Check that the power disconnector is set to OFF and the standby switch to .
5. Plug in the power supply connector at the power supply module.
6. Insert the backup battery/batteries, if applicable.
7. Close the cover.
8. Set the power disconnector to ON.
9. Set the standby switch of the power supply module to I (output voltages at rated
value).
10.Set the CPU mode switch to RUN if applicable.

How the S7-400 Behaves after Exchanging Modules

If an error occurs after replacing a module, you can read out the cause of the error
from the diagnostic buffer.

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 Maintenance

7.3 Replacing CPUs

Slot Numbering
If you have provided the modules in your system with slot numbering, you must
remove the number from the old module when replacing it and apply the number to
the new module.

Saving the Data

Save the user program including configuration data.

Removing the Module

1. Set the CPU mode switch to STOP.

2. Set the standby switch of the power supply module to (0 V output voltages).
3. Remove the cover of the CPU.
4. Disconnect the MPI connector, if applicable.
5. Disconnect the connector at the EXT. BATT. socket, if applicable.
6. Remove the memory card.
7. Loosen the mounting screws of the module.
8. Swing the module out.

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Maintenance

Installing a New Module

1. Attach the new module of the same type and swing it downwards.
2. Screw the module on.
3. If applicable, plug the connector for the external battery supply into the socket.
4. Set the CPU mode switch to STOP.
5. Insert the memory card.
6. Set the standby switch of the power supply module to I (output voltages at rated
value).
The remaining procedure depends on whether you use a Flash card and
whether or not you have configured your system for networking.
7. Proceed as follows to operate with a Flash card:
Transfer the user and configuration data.
Set the CPU mode switch to RUN.
Close the cover.
8. If your system is not configured for networking, proceed as follows:
Transfer the user and configuration data by means of the programming device,
via the programming device cable (see Section 6.3).
Set the CPU mode switch to RUN.
Close the cover.
9. If your system is configured for networking, proceed as follows:
Transfer the user and configuration data by means of the programming device,
via the programming device cable (see Section 6.3).
Set up your network by plugging in the MPI connector.
Set the CPU mode switch to RUN.
Close the cover.

How the S7-400 Behaves after Exchanging Modules

If an error occurs after replacing a module, you can read out the cause of the error
from the diagnostic buffer.

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 Maintenance

7.4 Replacing Digital or Analog Modules

Slot Numbering
If you have provided the modules in your system with slot numbering, you must
remove the number from the old module when replacing it and apply the number to
the new module.

Installing a Module
1. You can replace analog and digital modules in RUN mode. You must have taken
the appropriate action in your STEP 7 program to ensure correct responses
from your system.
If you are not sure whether your program will react correctly, set the CPU mode
switch to STOP.

Warning
! Improper handling of the front connectors can result in injury and damage.
If the front connector is removed and inserted during operation, hazardous
voltages of >25 VAC or >60 VDC may be present at the pins of the module.
When such voltages are present at the front connector, modules with power
applied may only be replaced by electrical specialists or trained personnel in such
a way that the pins of the module are not touched.

2. Loosen the mounting screw of the front connector and pull it off.
3. Loosen the mounting screws of the module.
4. Swing the module out.

Note
In order that the removal and insertion of digital or analog modules can be
detected by the CPU, a minimum time of two seconds must elapse between
removal and insertion.

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Maintenance

Removing the Front Connector Coding Key

Before fitting the front connector, you must remove (break off) the front part of the
coding key, because this part is already fitted in the wired front connector.

Caution
! The module can be damaged.
If, for example, you insert a front connector of a digital module in an analog
module, the module may be damaged.
Only operate modules with their complete front connector coding key.

Installing a New Module

1. Attach the new module of the same type at the appropriate slot and swing it
downwards.
2. Screw the module on with both mounting screws.
3. Fit the front connector.
4. If you have set the CPU to STOP, you must now set it to RUN again.
5. After fitting, each programmable module will be reinitialized by the CPU with
parameters.

How the S7-400 Behaves after Exchanging Modules

If an error occurs after replacing a module, you can read out the cause of the error
from the diagnostic buffer.

Exchanging the Front Connector

1. Switch off all load power supplies for the module.
2. Loosen the screw of the front connector and pull it off.
3. Remove the labels from the front connector and insert them into the new front
connector.
4. Wire the new front connector.
5. Insert the front connector in the module.
6. Screw the front connector on.
7. Switch on the load voltage.

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 Maintenance

7.5 Changing the Fuses in the Digital Modules

Modules with Fuses

The following modules have fuses which you can change yourself if they are
defective:
• Digital output module SM 422; DO 16 x DC 20--125 V/1,5A
(6ES7422-5EH10-0AB0)
• Digital output module SM 422; DO 16 x AC 20-120 V/2A
(6ES7422-5EH00-0AB0)
• Digital output module SM 422;DO 8 x AC 120/230 V/5A
(6ES7422-1FF00-0AA0)
• Digital output module SM 422;DO 16 x AC 120/230 V/2A
(6ES7422-1FH00-0AA0)

Check the Plant

Correct the faults which led to the fuses blowing.

Changing the Fuses

To change the fuses in a digital module, you must remove the front connector from
the digital module and remove the module from the rack.

Warning
! Improper handling of the digital modules can result in injury and damage.
Hazardous voltages of >25 VAC or >60 VDC may be present below the covers on
the right-hand side of the module.
Before you open these covers, ensure that either the front connector for the
module is removed or the module is disconnected from the voltage supply.

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Maintenance

Warning
! Improper handling of the front connectors can result in injury and damage.
If the front connector is removed and inserted during operation, hazardous
voltages of >25 VAC or >60 VDC may be present at the pins of the module.
When such voltages are present at the front connector, modules with power
applied may only be replaced by electrical specialists or trained personnel in such
a way that the pins of the module are not touched.

To change the fuses:

1. You must have taken the appropriate action in your STEP 7 program to ensure
correct responses from your system.
If you are not sure whether your program will react correctly, set the CPU mode
switch to STOP.
2. Loosen the mounting screw of the front connector and pull it off.
3. Loosen the mounting screws of the module.
4. Swing the module out.

Note
In order that the removal and insertion of digital modules can be detected by the
CPU, a minimum time of two seconds must elapse between removal and insertion.

5. Remove the covers on the right-hand side of the module by levering them out
with a screwdriver.
6. Replace the defective fuses with new fuses of the same type.
7. Place the guides on the covers into the appropriate cutouts in the module
casing and close the covers until they click into place.
8. Attach the module onto its slot and swing it down.
9. Screw the module on with both mounting screws.
10.Fit the front connector.
11.If you have switched the CPU to STOP, you must now switch it to RUN again.
12.After fitting, each programmable module will be reinitialized by the CPU with
parameters.

How the S7-400 Behaves after Replacing the Fuse

If an error occurs after replacing a fuse, you can read out the cause of the error
from the diagnostic buffer.

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 Maintenance

7.6 Replacing Interface Modules

Slot Numbering
If you have provided the modules in your system with slot numbering, you must
remove the number from the old module when replacing it and apply the number to
the new module.

Hot--swapping Modules
Observe the following warning when fitting and removing the interface modules and
the corresponding connecting cables.

Caution
! Data can be lost or corrupted.
If you remove or insert the interface modules and/or corresponding connecting
cables with power applied, data may be lost or corrupted.
Switch off the power supply modules of the CR and ERs on which you are working
before carrying out any actions.

Removing Modules / Exchanging Cables

1. If you wish to back up your data in the CPU, you can do this with a backup
battery or via an external battery supply at the CPU (see the CPU Data
Reference Manual, Chapter 1).
2. Set the CPU mode switch to STOP.
3. Set the standby switches of both power supply modules (in the CR and the ER)
to (0 V output voltages).
4. Remove the cover.
5. Disconnect the connecting cables.
6. Disconnect the terminator, if applicable.
7. Loosen the mounting screws of the module.
8. Swing the module out.

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