Mercury MR50 connections - Synergis Cloud Link

Synergis™ Cloud Link Hardware Installation Guide

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As part of your installation, you might need to include a Mercury MR50 interface module.

NOTE: For UL certified installations, the output from the MR50's K2 relay must not leave the room of installation and must be shorter than 30.5 m (100 ft.).
The following diagram demonstrates how to connect the module.
MR50-S3 unit with connections
A Reader connections Connect one reader.
NOTE: The wire colors in the illustration refer to "pigtail" HID readers; the information in parentheses refers to "terminal block" HID readers.
B RS-485 RS-485 bus connection to other Mercury modules.
C Line termination For modules at end of line, install jumper J4 (MR50) or J1 (MR50-S3) for 120 Ohm line termination.
D Address jumpers / DIP switches Used to set the device address. For more information on address settings on the Mercury module, refer to the manufacturer's instructions.
E Power In Connect + to VIN (observe polarity). Connect - to GND. Use 20 AWG wires minimum.
F Tamper input MR50: Normally closed switch (J3)

MR50-S3: Normally open switch (J2)

G Relay outputs
  • Relay 1: 5A inductive, 0.6 PF
  • Relay 2: 1A inductive, 0.6 PF
  • Relay 1: NO: 5A, NC: 3A inductive, 0.6 PF
  • Relay 2: 1A inductive, 0.6 PF
H Resistors For OSDP integrations, prevent readers from misinterpreting noise on a non-driven RS-485 line as data by installing a 1k ohm pull-down resistor from D0 to GND on TB4.

For wiring distances over 10 meters, install a 120 ohm termination resistor between D0 and D1, as well as between A (-) and B (+) on the RS-485 bus of the last connected reader.

To find out whether you need to add a 1K ohm pull-down resistor between D0 and GND, see KBA-78953.