Siemens installation manual How the S7-400 Behaves after Replacing the Fuse

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.

7-10	Automation System S7-400	Hardware and Installation
		A5E00850741-01