INSTRUCTIONS: Model 4683-TTM-xF
AC-Powered RS-485 Network Repeaters
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Acromag Incorporated, 30765 South Wixom Road
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P.O. Box 437
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Wixom, MI
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48393-7037, USA
Phone: (248) 295-0880
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Fax: (248) 624-9234
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E-mail: [email protected]
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On-Line: http://www.acromag.com
Copyright 1990, Acromag, Inc. Printed in the USA. 8500-758-C08H015
MODEL DESCRIPTION
Model Power
4683-TTM-1F
115V AC ±10%
4683-TTM-2F
230V AC ±10%
4683-TTM-3F
24VAC ±10%
These devices are “rugged” RS-485 network repeaters used for
isolating network signals and extending communication
distances. Model 4683-TTM-xF units are similar to the
Acromag Model 4SCR-TTM-x models, but add field-selectable,
End-Of-Line (EOL) network terminations on board for both the
A and B sides, are UL/cUL approved, and work at higher baud
rates.
Operation is transparent to all other network devices and no
handshaking is required. Up to 32 RS-485 devices can be
driven. These repeaters are enclosed in a rugged aluminum
enclosure and come ready to mount on any base plate, or can
be installed into a NEMA enclosure for harsh environments.
Installation is as simple as mounting, setting the baud rate,
connecting and terminating the network, and connecting power.
FEATURES
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Designed for use with Johnson Controls N2 or BACnet
MS/TP bus.
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No handshaking & No extra control lines required.
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Full I/O signal isolation.
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Supports baud rates of 600, 1200, 2400, 4800, 9600,
19.2K, 38.4K, and 76.8K, switch-selectable.
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Field-selectable, End-of-Line (EOL) network terminators on
both the A (input) and B (output) sides.
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Transient protection installed to help protect connected
devices from destructive noise spikes and line transients.
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Status LED’s indicate transmission direction, RS-485 bus
fault conditions, and power.
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115VAC, 230VAC, and 24VAC models supported (no
separate transformers are required for 24VAC models).
OPERATION
The Model 4683-TTM-xF network repeaters are used to isolate
and boost RS485 signals and extend network distance. Each
repeater will permit the addition of up to another 32 devices to a
network, and extend the communication distance another 4000
feet.
The repeater has two “sides” referred to as side A and side B.
Side A typically connects to the network towards the host (input
side). Side B connects to the extended network (output side).
Functionally, sides A and B are equivalent. Transient signal
protection is provided on both RS-485 sides. When both RS-
485 lines are idle, each side is in the receive mode. When a
one to zero transition is detected (signifying a start bit) on either
side, the opposite side’s transmitter is enabled (half-duplex).
The transmitter stays enabled for one character’s time (based
on the baud rate switch setting). The character received is then
passed through.
The repeater receives AC power through a three-screw terminal
strip. Input power is fused and isolated. Model 4683-TTM-1F
units require 115VAC, 4683-TTM-2F units require 230VAC, and
4683-TTM-3F units require 24VAC.
COMMUNICATION SPECIFICATIONS
Baud Rates:
DIP switch settings on unit for 600, 1200, 2400,
4800, 9600, 19.2K, 38.4K, & 76.8K baud rates. Only one
switch must be closed according to baud rate required for
proper operation.
RS-485 Bus Loading:
One unit load equivalent.
RS-485 Bus Drive:
Complete RS-485 compliance for up to 32
unit loads (31 unit loads if a repeater is used).
End-of-Line Termination Network:
Refer to Figure 1. The
EOL termination network is individually selected for both
the A and B sides by a pair of shorting clips. The A side
(input) is controlled by jumpers J1 & J2. The B side
(output) is controlled by jumpers J3 & J4.
The EOL network termination is enabled for the A side or
the B side when the associated pair of jumpers are
positioned over pins 1 and 2. The EOL termination is
disabled (removed from circuit) when the pair of jumpers
are positioned over pins 2 and 3.
Duplex:
Half duplex only.
Data Format:
Ten bits typical (1 start bit, 8 data bits, and 1
stop bit). Other formats are supported.
Status Indicators:
Red power LED; red RS-485 bus fault
LED’s, side A & B; green transmit LED’s, A-to-B & B-to-A.
PHYSICAL SPECIFICATIONS
Operating Temperature:
-25°C to 70°C (-13°F to 158°F).
Relative Humidity (RH):
10 to 95% RH (non-condensing), up
to 40° C (104° F).
Power:
115VAC ±10%, 50/60Hz, 0.05A (Model 4683-TTM-1F);
230VAC ±10%, 50/60Hz, 0.03A (Model 4683-TTM-2F);
24VAC ±10%, 50/60Hz, 0.18A (Model 4683-TTM-3F).
Power Line Fuse:
0.5A, 250V, 3AG type. Refer to Figure 1
for fuse location.
Isolation:
Unit includes galvanic and optical isolation between
RS-485 side A, RS-485 side B, AC power, and chassis
ground. Common mode voltages of up to 250Vrms, or
354V DC (withstands a 1500V AC dielectric strength test
for 1 minute without breakdown), are permitted on a
continuous basis. This complies with test requirements
outlined in ANSI C39.5-1974 for voltage ratings specified.
RFI Resistance:
Withstands RFI field strengths of up to 10V
per meter at 27MHz, 151MHz, and 467MHz with no digital
effect, per SAMA PMC 33.1 test procedures.
Line Noise Effects:
Field and power line terminals withstand
ANSI/IEEE C37.90-1978 Surge Withstanding Capability
(SWC) Test with no component failures. Unit is tested to
a standardized test waveform that is representative of
surges (high-freq. transient electrical interference),
observed in actual installations.
Communication Connections:
Network repeater – both RS-
485 connections use modular terminal blocks with screw
clamps. Wire range is 14 to 26 AWG.
Power Wire Connections:
Network repeater terminal block.
See label on unit for power to be applied to unit.
Approvals:
UL/cUL Listed, US & Canada, Energy
Management Equipment.
Shipping Weight:
3.0 pounds (1.4 kg) packed per unit.
