Specifications

ARCnet156
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6.7 Upgrading to ARC156
Before upgrading a legacy CMnet to ARC156, you must:
• Ensure adequate wiring. See 6.4 - Wiring Recommendations for details.
• Verify the network configuration is acceptable. See 6.2 - Segment Requirements.
• Use the appropriate network accessories—for example, 120 Ohm terminators and REP485
repeaters.
• Make sure all modules are capable of using Exec 6.0 or later. Refer to the Technical Instructions
for each module or to the Technical Handbook to determine this.
Follow these steps to upgrade the CMnet to ARC156:
1. While the CMnet is running at 38.4 Kbps or 9600 bps, transfer an Exec 6.0 (or higher) driver into
every module.
This can be done over a Direct Connection through a gateway module, or by setting the module for
38.4 Kbps or 9600 bps and Direct Network connecting to the module’s Access Port using an APT
in 485 mode.
2. Add a 120 Ohm terminator to each end of the network segment.
3. Add at least one ARC156-KIT to the middle of the network segment. Set the bias jumper to add
bias.
You can have more than one ARC156-KIT per network segment, but no more than one
ARC156-KIT should have the bias jumper set to add bias.
4. Go to each module and set the CMnet baud rate jumper for 156 Kbps communication.
Once you change the module’s baud rate, the module can no longer communicate on the CMnet.
When all modules are set to use 156 Kbps communications, a network reconfiguration is required
to start the ARC156 CMnet.
5. To reconfigure the CMnet immediately, remove and then restore power to one of the modules.
Otherwise, wait up to 30 minutes for the modules to reconfigure themselves.
6. Add other devices (like a REP485 or PROT485) to the CMnet as necessary to improve the signal
quality.
NOTE
A CMnet divided into segments may experience several reconfigurations until all the segments
are synchronized.