Considerations for OSDP reader installation with Mercury - Synergis™ Softwire 11.2

Synergis™ Softwire Integration Guide 11.2

Applies to
Synergis™ Softwire 11.2
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Guides > Integration guides
Synergis™ Softwire

Before adding OSDP readers to your Mercury controllers, read the following considerations.

Supported onboard OSDP readers with Mercury controllers

Refer to the following table to know how many OSDP readers Synergis™ Softwire supports with Mercury:
Model Onboard reader ports Max onboard OSDP readers per panel
MR50-S21 1 1
MR50-S3 1 1
MR52-S21 2 2 (one per port)
MR52-S3 2 2 (one per port)
MR51e 2 2 (two on one port only)
MR62e 1 4 (four on one port)
EP1501 2 2 (two on one port only)
EP1502 2 2 (one per port)
EP4502 2 2 (one per port)
LP1501 2 2 (two on one port only)
LP1502 2 2 (one per port)
LP4502 2 2 (one per port)
NOTE: Mercury EP2500 and LP2500 controllers are not listed because they do not have onboard reader ports. They support OSDP readers through the interface modules listed in the table.

1 Series 2 MR50 and Series 2 MR52 do not support OSDP Secure Channel.

Wiring instructions for OSDP readers

Depending on the assembly revision and PCB revision of your Mercury interface module and EP/LP controllers, specific installation requirements must be met:
  • A 1K-ohm pull-down resistor must be added between the Mercury DAT/D0 and GND lines on interface modules and EP/LP controllers.
  • The pull-down resistor must be installed on the panel.
  • To function properly, there must not be any ground faults in the installation. Ensure that the DC Ground (power supply return) is not connected to earth ground.
  • Wiring for Wiegand can be reused for OSDP. However, standard Wiegand cables might not meet RS-485 twisted pair recommendations.
  • Star-shaped wiring is not recommended.

To find out whether you need to add the 1K ohm pull-down resistor, see KBA-78953.

For more information about how to wire the OSDP readers, see Connecting Mercury interface modules in Synergis™ Cloud Link” in the Synergis™ Cloud Link Hardware Installation Guide.

Termination resistors

The following guidelines are especially important if you are working with high baud rate, for example, at 115,200 baud:
  • For OSDP cables longer than 200 ft. (61m) or EMF interference, install a 120 ohm resistor on both ends of the RS-485 daisy chain.
  • For Wiegand cables longer than 32 ft. (10m) or EMF interference, install a 120 ohm resistor on both ends of the RS-485 daisy chain.

If communication errors occur, you can lower the baud rate, add termination resistors, or both.