What can I check if my access control installation is not operating properly?
Below you will find a number of action points and tips to use to investigate your system and to detect any possible errors.
- Switch over from two-wire (a, b) to three-wire (a, b, P) for door intercom systems, or from five-wire to six-wire cabling for video intercom systems. Correct the jumpers.
- Check all connections (a, b, P, M, V1, V2) and take the polarity into account. At the same time, check for lost connections.
- Measure the voltage at the terminals of the internal and external units. Repeat this process, if necessary, with the power supply after you have disconnected all wires.
The correct voltage values are:
We recommend measuring at the terminal instead of on the screwhead.
- between terminals a and b (a = +): ± 24 Vdc
- between terminals b and P (P = +): ± 26 Vdc
- Push on a bell push button to check whether the external unit activates an audio signal.
- Check whether all jumpers or DIP switches are correctly positioned on the monitors, splitters and video receivers.
- Check whether the monitor is properly plugged into its fixing plate.
- If you combine a bus power supply and a direct current power supply:
- Use the positive terminal of the DC voltage power supply and not the P terminal of the bus power supply.
- Lay a bridging wire between the negative terminal of the DC voltage power supply and terminal b of the bus power supply.
- Double the wires from terminals P and M in case of greater distances and/or smaller wire diameters. This way, you are prepared for the drop in voltage.
- Manually program a hands-free device onto the first memory location of the bell push button. Immediately after releasing the speaker button, a second person pushes on the bell push button. You can also perform programming with the service unit.
- Test your installation by laying a separate cable between the camera and the monitor.
- Test your installation by connecting the monitor directly to the external unit.
- Pick up the receiver of the internal unit and check whether a green LED is illuminated at the internal unit and whether you hear noise from the street.
- Use a shielded cable with twisted pairs for a better image quality.
- The video external unit has an M terminal:
- If you connect the external unit with a six-wire system: connect terminal M with the negative terminal of the direct current power supply.
- If you connect the external unit in a five-wire system and/or use it in combination with a video power supply: lay a bridging wire between terminals b and M in the external unit or at the power supply.
- Set the potentiometers to the minimum and regulate both potentiometers uniformly to a higher volume. In the event of audio disturbances, resonance and high-pitched whistling tones, turn the potentiometers down a bit.
- In the event of electromagnetic disturbances from wiring in the vicinity, turn these circuits off temporarily.