Rockwell Automation 1791DS-IBxxxx Guard I/O DeviceNet Safety Modules - Manual (Page 102)

102 Rockwell Automation Publication 1791DS-UM001J-EN-P - May 2013
Chapter 6 Configure Modules in RSNetWorx for DeviceNet Software
2. In the Requested Packet Interval (RPI) box, enter the input connection
RPI to support your application (from 6…500 ms).
Selecting too small an RPI unnecessarily consumes network bandwidth;
selecting too large an RPI increases safety reaction time. Selecting the
appropriate RPI results in a system with optimized performance.
As an example, a safety input module with only ESTOP switches
connected to it generally may work well with settings of 50…100 ms.
An input module with a light curtain guarding a hazard may need the
fastest response that is possible.
A connection status tag exists that sums up all the safety I/O connections.
When the connection reaction time limit and requested packet interval are
set appropriately, these status tags should remain in their ‘no errors’
condition. Monitor these connection status bits to verify that they are not
changing intermittently due to timeouts.
IMPORTANT Analyze each safety channel to determine what is appropriate. The
default Time-out Multiplier of 2 and Network Delay Multiplier of 200
will create an input-connection reaction time limit of four times the RPI
and an output-connection reaction time limit of three times the RPI.
Changes to these parameters should be approved by a safety
administrator.
TIP We recommend keeping the Time-out Multiplier and Network
Delay Multiplier at their default values of 2 and 200.
Safety I/O Error Status
OFF No errors.
ON Errors exist in one or more of the safety connections.
Safety I/O Communication Status
OFF Errors exist in one or more of the safety connections.
ON No errors.