Eaton PDI JCOMM, Installation And Operation Manual

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Eaton PDI JCOMM Enclosure Installation and Operation Manual P-164001107—Rev 01 23
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This chapter describes incorporation of JCOMMs and their BCMSs into a network. Networking problems are
among the most common BCMS installation problems. Network addressing in particular should be carefully
planned.
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The networking protocol for JCOMM BCMS boards is Modbus RTU with the following characteristics:
• 9600 bps network speed
• Even (default), odd, or no parity (specified during BCMS software setup)
• 4-wire or 2-wire (2-wire selected by jumpers on the Connection Panel)
All customer Modbus network connections are made through two Modbus connectors on the Connections
Panel (
Figure 14 ). The customer provides Modbus cables for network connections.
Figure 14. Modbus Connections
All JCOMMs in a Modbus loop must be configured identically. 4-wire Modbus is the default. With a JCOMM
monitor, 4-wire Modbus must be used downstream of the monitor.
2-wire Modbus can be used on JCOMM network connections when a monitor is not installed. For 2-wire
Modbus loops, install jumpers connecting RX- to TX- and RX+ to TX+ on each JCOMM Modbus connector.