Rockwell Automation 1753-DNSI DeviceNet Safety Scanner for GuardPLC Controllers - Manual (Page 55)

Publication 1753-UM002A-EN-P - July 2005
Configure DeviceNet Nodes and Connections 5-13
Scanner Receive Timeout
The Scanner Receive Timeout is the amount of time (in milliseconds)
that the scanner waits for a request from the GuardPLC controller
before timing out the HSP connection. If the scanner does not receive
a message from the GuardPLC controller within this time, all output
connections are transitioned to the idle state, causing the safety
outputs to transition to the safety state and standard outputs to follow
the behavior dictated by their configuration.
Set the Scanner Receive Timeout equal to the Watchdog Timeout
specified on the Properties dialog of the controller resource in
RSLogix Guard PLUS! Hardware Management. Refer to the GuardPLC
Controller Systems User Manual, publication number 1753-UM001, for
information on setting the Watchdog Time.
Max. Scanner Response Time
The Max Scanner Response Time is the maximum amount of time (in
milliseconds) allotted for the scanner to process an HSP request from
the controller, and then format and send a proper response. If the
scanner cannot respond within this time frame, then all output
connections transition to the idle state, causing the safety outputs to
transition to the safety state and standard outputs to follow the
behavior dictated by their configuration.
The Max Scanner Response Time should be set to a value that
includes the maximum observed statistical scanner response time over
several hours of operation, plus a Margin of Safety equal to 3 ms or
10% of the maximum observed scanner response time. When online,
you can view the Minimum, Maximum, and Average Observed
Scanner Response Times by selecting the Statistics… button.