HID Mercury MR52-S3 Installations And Specifications page 9

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2.4 Alarm contract wiring
There are eight inputs that are typically used to monitor door position, request to exit or alarm contacts.
Input circuits can be configured as:
Unsupervised alarm (2 states); reporting as open or closed contact.
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Supervised alarm (6 states); reporting as open or closed contact, open circuit, shorted circuit, grounded
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circuit*, or foreign voltage*.
A supervised input circuit requires adding two resistors with value of 1kΩ, 1% to the circuit to facilitate proper
reporting and should be located as close to the sensor as possible. Custom end of line (EOL) resistances can
be configured via the host software.
*Grounded and foreign voltage states are not a requirement of UL 294 and therefore not verified by UL.
The input circuit wiring configurations shown are supported but may not be typical:
2.5 Inputs for cabinet tamper/power fault
Input CT and input BA are used for monitoring cabinet tamper and power failure with normally closed
contacts. These two inputs are for contact closure monitoring only, and do not use EOL resistor(s). If these
inputs are not used, install a short piece of wire at the input to indicate a safe condition.
PLT-05248, A.2
HID Mercury™ MR52-S3 Reader Interface
9
Installation and Specifications
June 2021