Q: |
What is Chopan?
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A: |
Chopan is a Tridium-developed protocol running over UDP/IP that is specifically designed to allow peer-to-peer data sharing
between 802.15.4 wireless devices and/or a JACE controller.
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Q: |
Why use Chopan?
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A: |
For point value updates, Chopan provides bandwidth efficiencies over Sox in wireless (Jennic-based) networks of devices, which
have notably less bandwidth than networks of Ethernet- and/or WiFi-equipped Sedona Framework devices. Chopan is also the only
way that Jennic-based devices can directly share data, peer-to-peer. Further, if a Jennic-based device is configured to “hibernate”
(noting Sedona Framework support for this is not widely available now), client “Chopan point” usage is required for point value updates in the NiagaraAX station—instead of Sedona proxy points. Such devices also use Chopan for other routines, such as “Maintenance Mode”.
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Q: |
Why not use Chopan?
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A: |
While using a Chopan tuning policy for Sedona Network proxy points is similar to using Sox, using the client interface for
Sedona devices involves configuration interfaces that may be abstract and unfamiliar to those familiar with NiagaraAX drivers.
Chopan does not use authenticated sessions and is less secure than the Sox protocol.
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Q: |
Is there an “easy way” to benefit from Chopan if I don’t have hibernating devices or don’t need to have devices share data directly, peer-to-peer?
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A: |
Yes: simply configure Jennic-based devices as Chopan servers. Then in the JACE station, for Sedona proxy points for those devices, specify tuning policies that use the “Comm Type” of
“Chopan”.
No Chopan client configuration of devices is required.
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Q: |
How does Chopan compare to Sedona Framework 1.0?
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A: |
Sedona Framework 1.0 uses Sox protocol for all communications. The JACE can poll or subscribe to data within a Sedona Framework
device, but all data sharing must go through the JACE.
The Sox protocol is designed around an authenticated session between a client and server. Each connection requires multiple
messages to set up and tear down and dedicated resources to maintain. This makes it unsuitable for general data sharing between
devices.
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Q: |
Does peer-to peer mean I don’t need a JACE?
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A: |
Every network of Jennic-based devices still requires a coordinator. This is an 802.15.4 networking requirement. At this point,
the only coordinators offered for deployment are the “Sedona Jennic” option card running in a JACE, or the USB Jennic adapter
(coordinator) for the Sedona Framework.
Note that the USB coordinator is intended for use in a developer scenario only, from Workbench to a single Sedona Framework device. There are no plans to support it as the coordinator to a “network of devices”—for example using
it with a AX SoftJACE or Windows-based JACE environment.
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