Rockwell Automation 1753-DNSI DeviceNet Safety Scanner for GuardPLC Controllers - Manual (Page 47)

Publication 1753-UM002A-EN-P - July 2005
Configure DeviceNet Nodes and Connections 5-5
of 10 ms. Other target devices may have more limited RPI
constraints. Consult the documentation for each type of target
device to determine its supported range and incremental values.
Modifying the RPI affects the Connection Reaction Time Limit.
For simple timing constraints, setting the RPI is usually sufficient.
However, for more complex requirements, use the Advanced…
button to further adjust the timing values affecting the
Connection Reaction Time Limit as described below.
6. Set the Advanced Safety Connection Properties (if required).
• Timeout Multiplier – The Timeout Multiplier determines the
number of RPIs to wait for a packet before declaring a
connection timeout. This translates into the number of
messages that may be lost before a connection error is
declared.
For example, a Timeout Multiplier of 1 indicates that
messages must be received during every RPI interval. A
Timeout Multiplier of 2 indicates that 1 message may be lost
as long as at least 1 message is received in 2 times the RPI (2
x RPI).
• Network Delay Multiplier – The Network Delay Multiplier
defines the message transport time that is enforced by the
communications protocol. The Network Delay Multiplier
specifies the round trip delay from the producer to the
consumer and back to the producer. You can use the
Network Delay Multiplier to reduce or increase the
Connection Reaction Time Limit in cases where the enforced
message transport time is significantly less or more than the
RPI.