Emerson 400518-01 installation manual Communications, Communication Cables

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Communications

Communications with the drive is provided through the RJ45 connectors located on the front of the drive. The two RJ45 connectors are identical and are used to provide a way to daisy chain two or more drives together using the DDC-RJ45 cable, see Figure 44. The Epsilon EP serial communication connector (serial port) as standard, supports 2 wire EIA485 communications. The RS-485 communications port is not isolated from drive electronics and the "0 V" pins are internally connected through a 10 Ohm resistor to PE. Interconnected drives should be within a zone of equipotential bonding. Connection to a master device on the network, such as a MMI, SCADA, PLC, or PR can be remote, but care should be taken to make sure the entire network operates within the +/-7 V common mode voltage range of RS-485. Though the comm port is part of PELV circuits when properly installed, if the master device is outside the zone of equipotential bonding the circuit needs to be isolated against direct contact. The minimal RS-485 network cable contains a shielded twisted pair for RX TX (pin 2) and /RX /TX (pin 7) with shield to the shell, though a 0 V reference signal (pin 3) can improve immunity to ground differentials. See the following table for the connection details for the RJ45 serial communication connector.

Pin	Function
1	120 ohm Termination resistor
2	RX TX
3	Isolated 0V
4	+15V (100 mA max)
5	Isolated 0V
6	TX Enable
7	RX/ TX/
8	RX/ TX/ (If termination resistors are required, link to pin 1)
SHELL	PE

The provision for connection of the internal 120 ohm terminating resistor at pin 1 and pin 8 would rarely, if ever, be needed unless data rates much higher than 19.2K are supported. Since a terminator connection is only made at the end of a trunk, it is most conveniently accomplished by crimping a short link from pin 1 to pin 8 in a new RJ45 connector and plugging it into the second RJ45 port on the "last" drive. Cable conductors should not be connected to these pins.

Communication Cables

The CT-Comms cable is an isolated RS-232 to RS-485 convertor that may be used to connect one or more EP drives to a master device using a standard 9 pin D-sub RS-232 serial comms port. The +15 V supply at pin 4 and the 0 V connection at pin 5 are intended only to provide power to the isolators in the CT-Comms cable and are not to be used for any other purpose.

The TX Enable signal at pin 6 and 0 V at pin 3 provide a transmit enable signal from each interconnected drive to a CT-Comms cable and are not to be used for any other purpose. They may be wired from drive to drive in a zone of equipotential bonding to allow the CT-Comms cable to communicate with all drives in the group.

The DDC-RJ45 provides drive to drive (daisy chain) connections between EP drives, including support for the CT- Comms cable in a group of drives.

Installation 37