The reader is not reading. Start here.
Six checks in the order that finds the fault fastest, and the reading to record at each one, so the second visit starts from data instead of scratch.
Work in this order
Reader faults overlap. A mode mismatch looks like a wiring fault, and an intermittent read looks like a card problem until you have ruled out noise.
This is the order Falco's own reader fault-finding guidance takes, tightened into six steps. Each one rules out a class of fault before you open a door or replace anything.
The six checks
Stop at the first step that fails. That is the fault.
- 01
Is the reader LED on?
No light means no power at the reader. The reader port carries the 12V feed, so check that output at the controller before anything else.
- 02
Verify the supply
Measure the power supply at the reader terminals, not only at the panel, and confirm it is the supply the reader needs (12V or 24V).
- 03
Check D0 and D1
D0 goes to D0 and D1 to D1. A reversed pair reads nothing, or reads the wrong number. A loose terminal reads intermittently and comes back next week.
- 04
Confirm the reader bit mode
Mode 1 for EM cards, mode 3 for MIFARE. When the reader's format and the controller's mode disagree, the card fails to read — set the mode and program the reader bits before replacing hardware.
- 05
Look for electrical noise
Reader cable beside mains cable, long unscreened runs and damaged cable all cause inconsistent reads. Use screened cable, re-route away from power lines, and check the ground.
- 06
Swap in a spare reader
If the settings and the wiring are correct and the fault stays, test with another reader of the same model. A working replacement means the reader was at fault.
Symptom to starting point
| What you see | Start at |
|---|---|
Reader LED off | Power: reader port output and supply |
Card reads at one door, not another | Reader bit mode and data wiring on the failing door |
Reads once, then stops | Supply under load, loose terminal, or noise on the run |
Reads the wrong number | Bit mode for that reader and card type |
Nothing reads after a reader change | D0/D1 reversed, or 12V and 0V swapped |
These are the causes Falco's reader fault-finding guidance names, in the order it names them.
Before you order a replacement reader
The reader LED and the supply voltage are recorded, not assumed.
The controller's bit mode for that door is written down and matches the reader model.
D0/D1 are terminated at both ends and not reversed.
The run is screened and clear of mains cable.
A spare reader of the same model has been tried at the same door.
The fault-finding checklist
The same six checks as a fill-in sheet: LED state, supply reading, D0/D1 termination, bit mode, cable route and spare-reader result, with a signature line for the handover.
No form. Download it, use it on site, and send the project our way when you want the model list priced.
Where this comes from.
Every technical statement on this page is drawn from Falco documentation. Nothing here is written to fill a page.
VAULT Site support documentation — in/out reader problem and troubleshooting guide: LED check, supply, D0/D1 reversal, mode mismatch, noise and the spare-reader test.
VAULT Site support documentation — RFID reader bit configuration: mode 1 for EM and mode 3 for MIFARE.
Falco controller wiring diagrams — reader port terminals and the 12V reader feed.