EIA-485 Network Terminator L-Term (EIA-485)

Features

? Supports termination of EIA-485 bus systems ? Applicable for

BACnet MS/TP Modbus RTU (RS-485) TP/RS-485 (CEA-709) CAN, CANopen, DeviceNet ? Resistance of 120 Ohm ? Screw terminals (0.5 - 2.5 mm2) ? Network access connector RJ-45 (LT-04 only) ? Biasing circuit for failsafe biasing (LT-B4 only)

Description

EIA-485 networks need to be terminated on both ends of the bus using defined network terminators.

The L-Term LT-04 and LT-B4 offer standard network terminators of 120Ohm to terminate a EIA485 channel, used for BACnet MS/TP, Modbus RTU over RS485, and TP/RS-485 (CEA-709) in DIN rail housings.

L-Term LT-04 is a terminator for EIA-485 channels. In addition, LT-04 comes with a network access connector (RJ45) for a simple and reliable connection to the network e.g. for maintenance or analyzing the network locally.

The LT-B4 is a bus terminator for an EIA-485 channel with biasing circuit (failsafe biasing). This biasing circuit draws the level of the bus during standby mode (idle) to a safe value (logic "1"). The LT-B4 needs a power supply of 24 VAC or 24 VDC.

With bus systems using EIA-485 technology only bus topology is allowed. Therefore, both ends of the cable must have terminators installed. This is necessary to keep up electronic communication.

Scheme of LT-B4

EIA-485 Network Terminator

L-Term (EIA-485)

ISSUE 2 DOCUMENT #890163 December 2010

GND 24V AC/DC NC

LOYTEC



L-Term

Bus Terminator LT-B4

RS-485 5V 510 510

120

+A B- NC

8

1

B

A

-

+

LOYTEC



L-Term

Bus Terminator LT-04

RS-485

A B NC +-

LT-B4

LT-04

LT-04 Modular Plug RJ-45(8P8C)

Pin

Marking

Description

1

A +

non-inverting pin, B (EIA-485)

2

B ?

inverting pin, A (EIA-485)

3 ... 8

NC

not connected

Dimension (mm)

18

58

53

24 VAC / VDC GND

+5V 510

+

120

-

510

90

GND 24V AC/DC NC

LOYTEC



L-Term

Bus Terminator LT-B4

RS-485 5V 510 510

120

+A B- NC

8

1

B

A

-

+

LOYTEC



L-Term

Bus Terminator LT-04

RS-485

A B NC +-

LT-B4

LT-04

buildings under controlTM

EIA-485 Network Terminator

L-Term (EIA-485)

Application Example

Modbus RTU: LINX100 Automation Server and terminator LTB4 with biasing circuit (failsave biasing)

GND 24V AC/DC NC

LPOW-2415B LOYTEC



Made in Austria

status

L-POW

Power Supply

Input 85-265VAC N L 50/60 Hz

24VDC/15W GND +

LOYTEC



L-Term

Bus Terminator LT-B4

RS-485 5V 510 510

120

+A B- NC

L-INX

OPC

ACT

21

RS-485

BA

1 23

FT

BA

4 56

Automation Server Made in EC

CNIP

LINK ACT CS/RNI

100Base-T

serial LOYTEC



LINX-100

power status

12-35 VDC INPUT or 12-24 VAC, 40-70 Hz

- + DC ~ ~ AC

15 16 17

Modbus Device

8

1

B

A

-

+

LOYTEC



L-Term

Bus Terminator LT-04

RS-485

A B NC +-

85-265 VAC 50 / 60 Hz

LT-B4

EIA-485 A Line (inverting) - , DA0 EIA-485 B Line (non-inverting) + , DA1

LT-04

Note: The labeling 'A' and 'B' on the L-Term Terminators differs from EIA-485 channel labeling.

Specifications

Dimensions (mm)

18 x 90 x 58 (L x W x H)

Weight

41g

Installation

DIN rail mounting (EN50022)

Operating temperature

0?C to 50?C (ambient)

Storage temperature

-10C to 85?C

Relative humidity

10-90% RH @ 50?C (non condensing)

Degree of protection IEC60529 IP20

Type

LT-04

LT-B4

Power supply

-

24 VDC or 24 VAC ?10 %

Power consumption

-

Typ. 175 mW (7.3mA) @ 24 VDC

Termination Impedance (Z)

120

For use with

BACnet MS/TP, Modbus RTU, Modbus ASCII via EIA-485 (RS-485), or LonMark TP/RS485 channel Bus topology, two terminators needed to terminate a bus

Order Number LT-04 LT-B4

Configuration 1 x EIA-485 (bus topology), 1 x Network access connector RJ-45 1 x EIA-485 (bus topology), 1 x Power supply for Biasing Circuit (failsafe biasing) 24 VDC/VAC

AST, "buildings under control", LC3020, L-Chip, L-Core, L-DALI, L-GATE, L-INX, L-IOB, LIOB Connect, LIOB FT, L-IP, L-MBUS, LPA, L-POW, L-Proxy, L-ROC, LSTUDIO, L-Switch, L-Term, L-VIS, L-WEB, and ORION stack are trademarks of LOYTEC electronics GmbH. Other trademarks and trade names used in this document refer either to the entities claiming the markets and names, or to their products. LOYTEC disclaims proprietary interest in the markets and names of others. LOYTEC reserves the right to make changes to these specifications without further notice for performance, reliability, production technique, and other considerations.

LOYTEC electronics GmbH, Blumengasse 35, 1170 Vienna, Austria ? info@ ? tel.: +43 (1) 402 08 05-0 ? fax.: +43 (1) 402 08 05-99

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