Siemens Industry Online Support
Siemens AG
Entry type: Product note Entry ID: 17738473, Entry date: 11/25/2003

Two Hard Disks and RAID1 Options for SIMATIC Box PCs 620/840

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The following new options are available for SIMATIC industrial PCs:
Two Hard Disks for the SIMATIC Box PCs 620/840 und RAID1 for the SIMATIC Box PC 840. These options will further increase the reliability and system availability of SIMATIC PCs in an industrial environment.

Even today, a lot of effort is being invested in SIMATIC PCs to ensure safe data storage and immunity against failure, with only one hard disk:

  • Robust drive holder design made of strong sheet metal
  • Tuned rubber buffers for the drive holder
  • Vibration test of the drive holder for critical resonances
  • Critical tests before release of the hard disk (vibration, shock, temperature)

Ruggedness and immunity against failure are demanded especially in industrial environments. These requirements are driven by the high costs of a plant standstill - costs produced by loss of production and service calls.

To lower these costs is our aim when we offer SIMATIC Box PCs 620/840 with even more reliability in the future: Two new PC options provide PC hardware with two hard disks, whereby one option has RAID1 functionality. These options will increase the system availability of SIMATIC PCs even more.


Technical Details: 2 HDD, RAID1

Hard disks

2 x 30 Gbyte, 2.5" - integrated in the hard disk unit

Hard disk unit

- Based on today's Box hard disk unit
- With rubber damping
- Tuned for vibration and shock damping

RAID Controller

RAID1 Hardware, module on PCI bus

Service friendliness

Very simple to dismantle:
- 4 screws, same as with today's hard disk unit
- 4 screws to remove the two integrated hard disks


No change
Even after the integration of two hard disks, the Box PCs can still benefit from their high compactness and remain unchanged in the housing dimensions.

SIMATIC Box PC620/840 option: Two hard disks

Two hard disks in a PC system provide the following features:

  • Quick and easy data saving
    The data of the "working hard disk" can easily be duplicated to the second "backup hard disk". If an operator error should damage the data on the working hard disk, they can easily be restored from the backup hard disk.
  • Saving of hard disk partitions
    By using a hard disk image software, e.g. the SIMATIC PC/PG Image Creator, complete partitions of the working hard disk can easily be stored on the second hard disk in the form of files. In the case of a fault on the working hard disk these data can be used to quickly and accurately restore the partitions - even on a replacement hard disk in the case of a repair.
  • Creation of a double, identical hard disk
    By using a hard disk image software, e.g. the SIMATIC PC/PG Image Creator, the complete working hard disk can easily be copied to become an accurate data image to the second hard disk - an identical image of the working hard disk is thus created. In the case of a fault on the working hard disk the second hard disk can quickly be switched over as working hard disk.

SIMATIC Box PC 840 option: RAID1

Automatic, redundant data storage (data mirror imaging on two hard disks) during operation of the PC with RAID1 offers the following:

  • High data availability
    Since data is held on two hard disks redundantly ("mirror hard disks") the probability of total data loss is reduced since it is very improbable that the two hard disks turn out simultaneous. In the case of a problem with one hard disk the user can continue to work until a self-defined point of time to exchange the faulty hard disk.
  • Very simple restoring of the data mirror image functionality
    If one of the two hard disks needs to be replaced, the newly installed hard disk will automatically be included in the RAID1 functionality - the mirror image data are created automatically.

User benefits
Both options provide a means to reduce costs in the case of a PC data problem, by:

  • Safe and simple local data storage
  • Low maintenance requirements
  • Small production losses by reduced or prevented plant standstill times in the case of a problem

Comparison: Two hard disks and RAID1


Option: 2 Hard Disks

Option: RAID1

Data availability

Data loss if the working hard disk fails

Very high
No data loss if the working hard disk fails

Handling of process data

Process data can be saved cyclically on the backup hard disk

Very good
Redundant and safe process data storage at any point of time (automatic data mirror imaging)

Data restoring in the case of an operator or application error

Very easy
Transfer the data from the working hard disk to the backup hard disk, e.g. by copying.

Data must be externally introduced to the RAID system, e.g. with a CD-ROM

System restrictions


1 x PCI slot less
(RAID1 controller module)


The new options are included in the IPC Configurators and can be ordered via the Siemens ordering procedures.

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