Device Properties - Redundancy - Siemens S7-200 Driver Manual

Siemens S7-200 Driver
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reached, the driver re-attempts to communicate with the non-responsive device. If the device is responsive,
the device is placed on-scan; otherwise, it restarts its off-scan time period.
Demote on Failure: When enabled, the device is automatically taken off-scan until it is responding again.
Tip: Determine when a device is off-scan by monitoring its demoted state using the _AutoDemoted
system tag.
Timeouts to Demote: Specify how many successive cycles of request timeouts and retries occur before the
device is placed off-scan. The valid range is 1 to 30 successive failures. The default is 3.
Demotion Period: Indicate how long the device should be placed off-scan when the timeouts value is
reached. During this period, no read requests are sent to the device and all data associated with the read
requests are set to bad quality. When this period expires, the driver places the device on-scan and allows for
another attempt at communications. The valid range is 100 to 3600000 milliseconds. The default is 10000
milliseconds.
Discard Requests when Demoted: Select whether or not write requests should be attempted during the
off-scan period. Disable to always send write requests regardless of the demotion period. Enable to discard
writes; the server automatically fails any write request received from a client and does not post a message
to the Event Log.
Device Properties — Redundancy
Redundancy is available with the Media-Level Redundancy Plug-In.
Consult the website, a sales representative, or the user manual for more information.
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