Campbell Scientific MD485 RS-485 Multidrop Interface - Manual (Page 18)

MD485 RS-485 Multidrop Interface
5.3 PakBus Networking
When configured to use PakBus protocol, the MD485 makes use of the
PakBus/Mdrop protocol on the RS-485 side. This allows reliable peer-to-peer
networking of multiple devices over the three-wire RS-485 interface.
When the communication mode is set to PakBus Networking, the MD485 does
not need to be represented in the device map of LoggerNet or PC208W. The
dataloggers are simply attached to a PakBusPort.
When using PakBus Networking, dataloggers must be set up with PakBus
addresses. They must also have beacons or neighbor filters set up as
appropriate. (Beaconing is used for most applications. Networks with RF401s
use neighbor filters.)
In PakBus Networking mode, datalogger-to-datalogger communication is
possible.
6. Combining with Other Devices
Besides the “direct” to PC communications described in the Quick Start and
System Configuration sections, it is possible to combine methods in datalogger
communications.
When using the MD9 emulation, PC400 software does not
support these combined communication options; use either
LoggerNet or PC208W software. NOTE
Some combined communications examples:
1) Phone to MD485: PC to external modem to COM220 to PS100 with A100
to MD485 to MD485 to datalogger (see Appendix A)
2) RF401 to MD485: PC to RF401s then through null modem cable (or
PS100 with A100) to MD485s to datalogger (see Appendix B)
3) MD485 to RF401: PC to MD485s then through null modem cable (or
PS100 with A100) to RF401s to datalogger (see Appendix C)
4) Cellular Digital Modem to MD485: PC to modem to Cellular Digital
Modem then through null modem cable to MD485 to MD485 to
datalogger (see Appendix D)
5) Network to MD485: PC to Internet to NL100 to MD485 to datalogger
(use LoggerNet IPPort or PC208W socket, remote IP address, port
number, see Appendix E)
The MD485 can also be used with the CC640 digital camera and the AVW200
Vibrating Wire Interface. When used with the CC640, the MD485 allows the
distance between the camera and a PakBus datalogger to exceed 25 feet (see
Appendix F). It is desirable to use the MD485 with an AVW200 for locations
where wireless communication is impractical, but the distance between
AVW200 interfaces needs to be extended (see Appendix G).
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