Cut Sheet

© 2016 Littelfuse Protection Relays & Controls
Protection Relays
Communication Modules
Rev: 1-A-062116
www.littelfuse.com/rs485ms2w
RS485MS-2W
Description
The RS485MS-2W is required to enable the Modbus
communications function on Model 77x-type products. This
module is required when the RM1000, RM2000 or other
Modbus capable device is used with 77x-type products.
Features

Optical isolation from line potentials

Powered by the 77x product

RS-485 compliant bus drive capability

Remote reset input connection

Power connection for the Model RM1000
Accessories
RS485-RS232 Converter with cable & plug
Allows RS485 devices to be connected to a PC
via the RS232 (serial) port. Provides convenient
terminal blocks for making signal and DC power
supply connections. Pre-wired.
RS485-USB
Converter with cable & plug/RS232:USB
Allows RS485 devices to be connected to a PC
via the USB port. Provides convenient terminal
blocks for making signal and DC power supply
connections. Pre-wired.
Communication Module
Wiring Diagram
TYPICAL RS485 NETWORK
Refer to the manual for basic and extended network diagrams.
Specifications
Functional Specifications
Remote Reset (for optional
use with 777 Series) Normally open pushbutton rated 24VDC,
10mA (min.)
General Characteristics
Ambient Operating
Temperature -20° to 50°C (-4° to 122°F)
Terminal (depluggable
terminal block)
Torque 3 in.-lbs. (max.)
Wire AWG 12-20 AWG
Class of Protection IP20
Relative Humidity 10-95%, non-condensing per IEC 68-2-3
Standards Passed
Electrostatic Discharge (ESD) IEC 61000-4-2, Level 3, 6kV contact, 8kV air
Radio Frequency
Immunity, Radiated 150 MHz, 10V/m
Fast Transient Burst IEC 61000-4-4, Level 3, 4kV input power
Hi-Potential Test Meets UL508 (2 x rated V + 1000V for 1 min)
Surge
Input Power IEC 61000-4-5, Level 1
Inputs/Data Lines IEC 61000-4-5, Level 2
Safety Marks
UL UL508 (File #E68520)
CE IEC 60947
Enclosure Polycarbonate
Dimensions H 52.83 mm (2.08”); W 73.66 mm (2.9”);
D 19.56 mm (.77”)
Weight 0.26 lb. (4.16oz., 117.93 g)
Mounting Method 9-pin D-Sub connector on the side of a
777-Series