Guardian Duo Troubleshooting Guide

Overview

This guide provides troubleshooting procedures for the Guardian Duo Accessible Pedestrian Signal (APS) system. These procedures help identify common issues related to installation, wiring, station communication, and device configuration.

The Guardian Duo system consists of:

• Guardian Duo Accessible Push Button (APB)

• Duo Controller

• Duo Power Supply

Proper operation of all three components is required for the system to function correctly. (Excluding RRFB operation)

Troubleshooting typically involves verifying cabinet power, field wiring, station discovery, and device configuration.

System Not Powering On

If the Guardian Duo system does not power on, verify the Duo Power Supply is receiving cabinet power and providing output to the Duo Controller.

Check the following:

Power Supply Input

• Verify cabinet AC power is present

Power Supply Output

• Verify 16 VDC output from the power supply

Controller Power Connection

• Confirm power wiring between the power supply and Duo Controller is secure

If power is present and the controller does not power on, inspect wiring connections or replace the power supply.

Guardian Duo APBs Not Powering On

If the Duo Controller has power but the Guardian Duo APBs do not, verify the connections between the Guardian Duo APBs and the Duo Controller card.

Check the following:

Card Seating

• Verify that the Duo Controller card is fully seated in the card rack

Field Wiring

• Confirm field wires from the cabinet to the push button station are intact

Field Terminations

• Verify that the field wires are connected to the correct terminals for the chosen card rack slot. The correct terminals will be energized with 15V DC.

Voltage

• Voltage at the button should read between 11 and 15V DC

Polarity

• If field terminations are correct but no voltage is present at the button, check wiring polarity

Push Button Does Not Register a Pedestrian Call

If a push button press does not register at the traffic controller, verify the pedestrian call wiring and controller configuration.

Check the following:

Call Output Configuration

• Verify presence and position of jumpers on P402 in the lower left corner of the Duo Controller card. Models shipped prior to April 2026

• Verify position of the Call Output Configuration Switch in the lower left corner of the Duo Controller card. Models shipped after April 2026

Cabinet Style

• Verify style of cabinet. DB9 cable is commonly used with NEMA cabinets, while 332 and ATC cabinets more commonly place calls through the card rack

• DB9 cable is not recommended for 332 cabinets, which are set up to accept calls through the card rack by default. There is a high probability of miswiring, leading to abnormal behavior

Calls through DB9 Cable

• If jumpers or switch are configured for call outputs through DB9 cable, verify that the cable is present and wired correctly

Calls through Card Rack

• If jumpers or switch are configured for call outputs through the card rack, verify that the card is fully seated and that the controller is configured to accept pedestrian calls through the rack

Field Wiring

• Confirm field wires from the cabinet to the push button station are intact

Station Discovery

• Ensure stations have been detected by the controller

Press the SET button on the Duo Controller to re-run station discovery if necessary.

Station Not Detected During Discovery

If a push button station is not detected during discovery, inspect field wiring and controller channel connections.

Check the following:

Field Wiring Continuity

• Verify two-wire field wiring between the cabinet and station is intact

Controller Channel Wiring

• Confirm wiring is connected to the correct controller channel terminals

Station Connections

• Verify wiring connections at the push button station are secure

After correcting wiring issues, run station discovery again.

Station Detected but Not Responding

If a station appears during discovery but does not respond to button presses, verify the station is correctly associated with the pedestrian phase.

Check the following:

Pedestrian Phase Assignment

• Verify the station was correctly assigned during discovery

Controller Inputs

• Confirm the walk and don’t walk signals are correctly wired

Field Wiring

• Confirm field wires from the cabinet to the push button station are connected to the correct phases

Controller Channel

• Verify the station is connected to the correct controller channel

Run station discovery again if phase assignments appear incorrect.

Audible Messages Not Playing (or Red LED Won’t Clear)

If the station does not produce audible messages during the walk phase, verify configuration and system operation.

Check the following:

Pedestrian Signal Inputs

• Verify walk and don't walk inputs are correctly connected to the Duo Controller

Cabinet Type

• Verify the type of cabinet. 332 and ATC cabinets use a different channel-to-phase mapping than NEMA cabinets and may require rewiring the walk and don’t walk inputs

Pedestrian Walk Signal

• Confirm the traffic controller is sending a walk signal

Audio Configuration

• Verify audio files are installed and active

Volume Settings

• Confirm locator and walk message volume levels are set appropriately

Configuration can be verified using the PedConnex application.

Locator Tone Not Audible

If the locator tone cannot be heard at the station, verify volume settings and night mode configuration. Also verify that the station has been discovered.

Check the following:

Discovery

• Confirm that the station has been discovered and run station discovery if it has not

Locator Tone Volume

• Confirm locator tone volume is not set to minimum

Night Mode Settings

• Verify nighttime volume levels are not excessively reduced

Audio Files

• Confirm locator tone audio files are present on the device

Adjust configuration settings using the PedConnex application if necessary.

Unable to Connect Using PedConnex - Bluetooth

If the device cannot be accessed over Bluetooth using PedConnex on iOS or Android, verify the device is powered and within communication range.

Check the following:

Bluetooth Enabled

• Confirm Bluetooth is enabled on the mobile device

Bluetooth Advanced Security

• Press and hold the Guardian Duo APB pushbutton for 8 seconds before trying to connect to Bluetooth. This is not necessary if Advanced Security is disabled and Bluetooth is set to Always ON.

• The red LED with flash once per second when bluetooth is enabled.

• Bluetooth will broadcast for 1 minute unless a connection is made. Press and hold the button for 8 seconds if connection was not made before timing out.

Device Power

• Verify the Guardian Duo station is powered

Connection Range

• Move closer to the device during connection attempts

Restart the PedConnex application if connection problems persist.

Unable to Connect Using PedConnex - USB

If the device cannot be accessed over USB using PedConnex on Android or Windows, verify the device is powered and communicating properly.

Check the following:

Windows COM Port Generation

• Confirm that a COM port is generated upon plugging in the USB cable, using the PedConnex Advanced tab

Windows COM Port Detection

• If a COM port is generated but still cannot connect, use the PedConnex Advanced tab to manually select the correct COM port

Android USB Detection

• Verify that Android has detected the USB device. If not, unplug the USB, close and restart PedConnex, and plug in the USB with the app active

Device Power

• If primary power is not supplied to the terminal block, verify that the USB cable is powering the Guardian Duo APB. Red LED should flash when cable is plugged in

System Operation Verification

After correcting any issues, verify proper system operation.

Test each station and confirm the following:

Pedestrian Call

• Push button press registers at the traffic controller

Wait Indication

• Wait message and LED activate after button press

Walk Indication

• Audible walk message plays during walk phase

Vibrotactile Feedback

• Vibrotactile indicator activates during walk phase

Locator Tone

• Locator tone resumes during clearance phase

Verify operation at each pedestrian crossing location.

Downloads

Guardian Duo User Manual

Guardian Duo Wiring Quick Guide