Before adding OSDP readers to your Mercury controllers, read the following considerations.
Supported onboard OSDP readers with Mercury controllers
|Model||Onboard reader ports||Max onboard OSDP readers per panel|
|MR50-S3||1||2 (two on one port)2|
|MR52-S21||2||2 (one per port)|
|MR52-S3||2||4 (two per port)2|
|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||4 (two per port)2|
|LP4502||2||4 (two per port)2|
1 Series 2 MR50 and Series 2 MR52 do not support OSDP Secure Channel or two OSDP readers per port.
2 Starting in Synergis Softwire 11.3.1 and Security Center 18.104.22.168, two OSDP readers per port are supported through the Two OSDP readers per reader port setting configured on the Mercury controller settings page in the Synergis™ Appliance Portal.
Wiring instructions for OSDP readers
- 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 resistorsThe 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.