The Common important errors in the installation of access control systems

What’re The common important errors in the installation of access control systems?

1, Use the network cable to connect the electric lock and access controller!

The line from the electric lock to the access controller in the access control system installation looks very ordinary. If it is not standardized, it is easy to cause a fault phenomenon that is not easy to find the cause. This must be taken seriously.
Since the electric lock has a relatively large operating current (relative to other devices of the access control system such as the controller and card reader), the electric lock has a certain distance from the controller, and the voltage drop on the line is relatively large. If the pressure drop is too large, the electric lock will sometimes be carried, sometimes with no movement. Magnetic locks sometimes have insufficient suction. The performance of the door switch is not normal. It will even grab the current resources with the access controller, making the controller power shortage, restarting or even crashing.
Some engineers have convenient wiring at the moment, or easy to purchase. It is easy to cause troubles when using the network cables to connect electrically lock and the access controller board. Although it seems that there is no problem during debugging, after a while, problems often occur.
Suggestions from the electric lock to the access controller line:

• If the line length is less than 50 meters, it is required to use a two-core power line with a cross-sectional area of 1.0 square millimeter, without shielding.
• If it exceeds 50 meters, please double the cloth with a two-core power line and supply power in parallel.
• If the line length is greater than 100 meters, it is recommended to move the controller closer to the position of the door lock to shorten the wiring distance.
• The cross-sectional area of the network cable is 0.2 square millimeters, which is 5 times smaller than our standard wire, so it is absolutely impossible, even if the controller is close to the electric lock.

The electric lock door magnetic signal line can be a network cable. Some people, the four shares of the network cable, to power the electric lock, although theoretically close to the norm, but it is not recommended. Doing so will cause other hidden dangers such as unstable terminals

2, The power load is too large to load! The main performance is that there are too many electric locks were connected

Power allocation recommendations for door access control systems

A double-door magnetic lock is the power of two single-door magnetic locks. If the system exceeds this configuration, for example, 4 or more electric drop blot locks or more than 3 magnetic locks, it is necessary to add a power supply and the original power distribution.

If the power is not enough, it will not be shown when debugging, unless it is not enough. It appears that sometimes the door is locked, sometimes it can’t be locked, and even the access controller can grab current, causing the access controller board to restart or even crash.

Because the access control linear power supply has low effective power and heat, the effective power is generally 40-70%, and the nominal 5A power supply has an effective current of about 3A. However, the linear power supply operates stably with less interference and is suitable for long-term stable operation of the equipment. It is the type of power commonly used in external access control system equipment. Some engineers ask whether the switching power supply can be used, switching power supply is high, and effective power is high. We do not recommend switching power supply. Switching power supply generally has a high-frequency ripple, which will affect the stability of the host operation.

3, 485 lines do not use twisted pair, or use low-end passive converter!

The 485 communication line cannot be star-connected. It is necessary to follow the standard hand-held bus mode. If the 485 trace is not standardized or exceeds the communication range, there will be a phenomenon that communication is not possible or sometimes communication is not possible.

485 transmission is the differential mode transmission mode. Only 485+ and 485- are twisted pairs, which can make the 485 transmission mode suffer the least interference, the transmission is the farthest, and the transmission quality is the best. Some engineering companies do not use twisted pairs, which will make the interference very large. Some engineers mistakenly think that the transmission quality of the line will be better, the twisted pair will be synthesized, and the other twisted pair will be combined. This is counterproductive. Instead, the quality of communication is greatly reduced.

There is a small converter on the market that does not have a power supply, which is cheap. However, the anti-interference performance is not good, and it is generally used for indoor short-distance communication of a single machine, such as an attendance machine. Not suitable for access control systems. Although it claims to be able to carry 32 devices and has a transmission distance of 1000 meters, it is often far from the target in practical applications. So it is recommended that you do not use this passive converter. Unless it is indoors, the communication distance is less than 100 meters, and the number of loads is less than 2, which can be considered from the perspective of cost. Otherwise, it is highly recommended that you use an active 485 converter that is not expensive and much more stable. The number of load controllers is also large. Anti-interference, lightning protection, the anti-surge effect is also very good.

The 485 wiring prohibits the star connection, that is, it cannot be pulled from the converter to each controller separately, and then connected in parallel on the converter. This connection makes the communication quality very poor. Be sure to come out of the converter, first to a controller, and then to the next control, one after another, like a string of grasshoppers.

Non-standard 485 wiring, even if it is improved with shielded grounding terminal resistors in the future will not help.

4, Other matters need to pay attention

• Without consulting and understanding, you can not connect some non-access control systems devices(such as automatic doors or elevators); each external device, even different manufacturers of the same equipment, have different electrical characteristics. Unfamiliar, it is easy to cause the instability of the access control system, and a lot of interference, so please communicate with the technical staff of the access control factory before the external equipment, gain some experience, and also strengthen the electrical performance of the external equipment. Familiarity and improvement and precipitation of the engineer’s own technical experience.
• When the customer sometimes refers to replacing the product with other products, the line is already laid, and when the line cannot meet the specification requirements, the line must be re-arranged, and the standard cannot be used. Nowadays, if you save trouble or luck, it will inevitably cost a lot of money and energy for future work.