Rockwell Automation 1756-DHRIO_DHRIOXT ControlLogix Data Highway Plus-Remote I/O Communication Interface Module - Manual (Page 24)

24 Rockwell Automation Publication 1756-UM514C-EN-P - June 2014
Chapter 2 Using the Data Highway Plus Network
Application Guidelines
Consider the following application guidelines when configuring a DH+ link for
your system:
• Minimize the number of DH+ nodes to achieve acceptable response times.
Keep in mind the size and frequency of messages exchanged between
devices.
• Limit the number of stations on your network when you are trying to
achieve the fastest control response time. Establish separate DH+
networks to bring-on additional stations.
• Do not add or remove stations from the network during machine or
process operation. If the network token resides with a device that is
removed, the token can be lost to the rest of the network. The network is
automatically reestablished, but it could take several seconds. Control is
unreliable or interrupted during this time.
• When possible, do not program controllers online during machine or
process operation. This could result in long bursts of DH+ activity,
increasing response time.
• When possible, add a separate DH+ link for programming processors to
keep effects of the programming terminal from the process DH+ link.