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No Communication
When the Central and/or Remote unit is not communicating with its partner, the status LED will flash green/red. To
troubleshoot communication issues, check the following:
•
Power:
• Both units must be powered.
• Ensure proper power requirements are met: Unregulated Input 8 to 16Vdc @ 300mA max.
•
Installation:
• Ensure the RS-485 connection between the Central and Remote unit is straight through, not reversed.
• Ensure the two conductors are not broken. This can be tested by twisting the two conductors together at
one end and testing continuity between the two conductors at the other end. If there is continuity
between the two conductors then the cable is good.
• Ensure the Central and Remote unit are connected with the proper RS-485 port. The RS-485 port on the
8 pin header is for the EXP-2000 expansion modules. The RS-485 port for communication between the
Central and Remote is on the 2 pin header located on the same side as the 10 pin header.
• Ensure the cable being used for connection between the Central and Remote is the proper type of cable
for the distance between the Central and Remote locations.
•
Configuration:
• Ensure both Suprex units are set to the correct link type. (see Configuration Mode, pgs. 7-9)
• Ensure Suprex units are properly configured as a Central and Remote pair. (see pgs. 25-26)
No Data / Invalid Data
If the access control panel is not receiving valid data, check the following:
•
Basic
Equipment Check:
• Ensure the reader and the access control panel data port are functional by directly connecting the reader to the
data port and passing card data.
• Check Suprex circuit boards for any signs of visual damage, such as burnt traces, burnt components, or
browning of the PCB; these usually indicate misapplied power.
•
Wiring:
• Ensure there is a common ground between the Remote unit and the card reader.
• Ensure there is a common ground between the Central unit and the access control panel.
• Ensure Wiegand data wires are correctly connected and not reversed.
•
Configuration:
• Ensure both Suprex units are set to the correct interface type. (see Configuration Mode, pgs. 7-9)
• Ensure the access control panel is properly configured for the selected data format.
•
Data Voltage:
For a Wiegand connection, ensure Data 0 and Data 1 pins on Central and Remote units are at 5V
relative to ground. The data pins can be as low as 4.4V before failing. If any Wiegand data pin is less than 4.4V, it is
necessary to identify which device is pulling down the voltage.
• Disconnect the Suprex from the reader/panel.
• Maintain power on the Suprex and the reader/panel.
• Independently measure the voltages of the Wiegand data pins of the Suprex, and of the reader/panel. If one or
both devices have 4.3V or less, try enabling the pullup resistors on the Suprex by turning on DIP switch 5.
• If internal pullup resistors do not work, try external pullup resistors (through-hole resistor 500ohms - 2Kohms). To
install external pullup resistors, place one end of the through-hole resistor into the +5Vdc pin on the Suprex unit;
place the other end in the low-voltage Wiegand data pin. (see pg. 5)
Cypress Suprex® RS-485 Series - Troubleshooting
