| To configure a redundant disk device set
up the following records in your project.
IO Server:
IOSERVER1
IOSERVER2
IO Devices:
| Server Name: |
IOSERVER1 |
| Number: |
1 |
| Address: |
C:\Primary.cdk,X:\Standby.cdk |
| Protocol: |
GENERIC |
| Port Name: |
DISKDRV |
| Startup Mode: |
Primary (enable Extended Forms to see this
field) |
| Server Name: |
IOSERVER2 |
| Number: |
1 |
| Address: |
C:\Standby.cdk,X:\Primary.cdk |
| Protocol: |
GENERIC |
| Port Name: |
DISKDRV |
| Startup Mode: |
StandbyWrite |
Note: do not leave a space after the comma and before the
other units drive letter in the Address fields.
- Use the Computer Setup Wizard to Configure two PCs as
IOServers. ie IOSERVER1 and IOSERVER2.
- Map the C drive of the remote PC to the local drive letter X
(NB must first have the C drives shared - use Windows Explorer to
do this)
- Run the projects and confirm that the files: Primary.cdk and
Standby.cdk get created on IOSERVER1 and IOSERVER2
respectively.
- To test: Configure a digital test tag, shutdown the primary
IOServer IOSERVER1, and toggle the bit on IOSERVER2. Restart
IOSERVER1 and check that the value has been updated.
NOTES:
- It is critical that both IODevices have the same number.
- You can use path substitution in the IODevice address field,
for the primary file only. ie substitute C:\Primary.cdk in the
first record and X:\Primary.cdk in the second record. Note that
this path substitution restriction has been lifted in recent Citect
versions.
- Ensure the Date, Time and Daylight Savings regional settings in
the Windows Control Panel are the same on both PCs. Otherwise, the
timestamp on the disk files will be inconsistent and the older file
may be copied over the newer file at startup (resulting in the loss
of the latest changes to disk device variables).
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