Available Communications Protocol Selection And Wire Spec; Ethernet - Toptech MultiLoad III Installation Manual

CHAPTER 4– DATA COMMUNICATIONS INTERFACE
Separate AC and DC wiring by at least 3 inches [75mm]. Do not allow excess wire in the
service loop to overhang printed circuit board.
Default settings in MultiLoad are: COM O – FCM ; COM 1- HOST , COM 2- NA and COM3
– NA. See the user guide for more details.
Only one port may be configured as an FCM, Print or Alibi Log function, otherwise a 'Port
Usage Conflict(s)' message will display upon re-boot. See the user guides for more details.

Available Communications Protocol Selection and Wire Spec

This section describes the available communication protocols for MultiLoadIII/RCU III DIV2 Hardware.

Ethernet

The Ethernet ports use HP Auto-MDIX technology. By automatically detecting the signaling on the
connected device, the transceiver will configure the port directions automatically. Thus, the choice
of a straight through or cross over cable no longer must be made—either will work.
Wire used must meet the following characteristics:
-
Ethernet wiring standard T568B - Cat5 cable (or greater).
RS-422/485
The RS-422/485 communications protocol is designed for multi-point (i.e., computer to multiple
devices, also called multi-dropped) communications up to 4,000 feet (1,220 Meters).
RS-422 requires 4-wires (2 twisted pair) for full duplex communications and utilizes a transmit pair
of wires (TDA & TDB) and a receival pair of wires (RDA & RDB).
RS-485 requires 2-wires (1 twisted pair) for half duplex communications and utilizes a single pair
of wires (TDA/RDA & TDB/RDB) for transmittal and receival
This manual will typically refer to both RS-422 and RS-485 as simply RS485 2 Wire or RS485 4
Wire.
Although a ground wire is not required, the common mode voltage between the MultiLoad
III/RCU III DIV2 Hardware and the field devices must be within -7Vdc to 12Vdc. To
correct situations where this is not the case, the DC GND is available on all serial ports.
Connect the MultiLoad III/RCU III DIV2 Hardware DC GND to the signal ground of the field
device.
Wire used must meet the following characteristics:
- 24 AWG stranded.
24
MultiLoad III/RCU III DIV2 Hardware Installation Guide - Part # 6074