Access control construction common error phenomenon one

Use network wire cloth electric lock to lock the controller wire!

 Access control construction from the electric lock to the controller of a line, looks very ordinary, if not standardized it is easy to cause trouble, this must be paid attention to!

 Because the working current of the electric lock is relatively large (compared with other devices of the access control system, such as the controller card reader), the electric lock has a certain distance from the controller, and the voltage drop on the line will be relatively large. If the pressure drop is too large, it will make the electric lock sometimes move, sometimes do not move. Magnetic locks sometimes don't have enough suction. The door is not open and closed properly. It will even rob current resources with the controller, making the controller insufficient power supply, restart or even crash.

 Some engineers figure that the wiring is convenient, or the procurement is convenient, the use of network wires to distribute the electric lock to the controller wire, it is easy to cause failure, although there seems to be no problem when debugging, after a period of time, there will often be problems.

 If the length of the cable from the electric lock to the controller is less than 50 meters, it is required to use a two-core power cable with a cross-sectional area of 1.0 square mm without shielding. If the cable is more than 50 meters, it is necessary to double and distribute one more two-core power cable for parallel power supply. If the line is longer than 100 meters, it is recommended to move the controller closer to the position of the door electric lock to shorten the wiring distance.

 The cross-sectional area of the cable is 0.2 square millimeters, which is 5 times smaller than our standard wire, so it is absolutely not possible, even if the distance between the controller and the electric lock is very close. Electric lock door magnetic signal cable, network cable can be used. Some people, four strands of the network cable in one, to power the electric lock, although in theory is close to the norm, but it is not recommended that you do so. Doing so will make the terminal unstable, etc

Access control construction common error phenomenon two

Power load is too large load! The main performance is too much electric lock! Power configuration suggestions for the access control system

 The standard configuration power supply provided by nabon company is 12V, 4A switching power supply. It can meet (wiring specifications, line cross-sectional area is thick enough) up to four doors (5 electric plug-in locks or 4 magnetic locks) power supply. A double door magnetic lock is converted into the power of two single door magnetic locks. If the system exceeds this configuration, for example, more than 5 electric locks or more than 4 magnetic locks need to add a power supply and the original power supply to distribute power.

 Note: If some electric lock power is too large, the power supply will be weaker on its load capacity.

 If the power is not enough, it will not necessarily show when debugging, unless it is very insufficient. Sometimes the door lock can be locked, sometimes it cannot be locked, and even the controller will rob the current, making the controller restart or even crash.

Access control construction common error phenomenon three

485 lines do not use twisted pair, or use a low-grade passive converter! 485 communication line can not go star connection, must go the standard hand in hand bus mode.

 If the 485 wiring is not standardized or beyond the scope of communication, there will be no communication or sometimes communication on sometimes communication phenomenon.

 485 transmission is a differential mode transmission mode, only 485+ and 485- each other in twisted pairs, in order to make 485 transmission mode subject to the least interference, the farthest transmission, the best transmission quality. Some engineers do not use twisted pair will make the interference is very large, some engineers mistakenly think that the line thicker transmission quality will be good, the twisted pair will be synthesized a strand, another twisted pair is also synthesized a strand, which is counterproductive, but greatly reduce the quality of communication.

 There is a small converter on the market that has no power supply and is cheap. However, the anti-interference performance is not good, and it is generally used for single-machine indoor short-distance communication, such as attendance machines. Not suitable for access control systems. Although it claims to be able to take 32 devices and transmit distances of up to 1000 meters, in fact, it is often far from reaching the target in practical applications. Therefore, it is recommended that you do not use this passive converter. Unless indoors, the communication distance is less than 100 meters, and the load is less than 2 units, it can be considered from the cost point of view. Otherwise, it is highly recommended that you use an active 485 converter, which is also less expensive and much more stable. The number of load controllers is also large. Anti-interference, anti-lightning, anti-surge effect is also very good.

 485 cabling prohibits star connections, that is, do not pull cables from the converter to each controller, and then parallel on the converter. This connection makes for poor communication. Be sure to come out of the converter, first to a controller, and then connected to the next control, a connected down, like a string of grasshoppers.

 Non-standard 485 wiring, even if it is improved by shielding the grounding terminal resistance in the future, is of no use.

Common major errors in access control construction wiring _ Other precautions

 First, without consultation and understanding, connect some equipment that is not the access control system itself (such as automatic doors or elevators); Each external equipment, even different manufacturers of the same equipment have different electrical characteristics, if you are not familiar with these characteristics, it is easy to cause the instability of the access control system, and produce a lot of interference, so please communicate with the technical personnel of the access control manufacturer before connecting the equipment, gain some experience, and also strengthen the familiarity with the electrical performance of the external equipment. And the improvement and precipitation of engineers' own technical experience.

 Second, the customer sometimes mentioned to replace this product with other products, the line has been laid, the line can not meet the requirements of the specification, the line must be rearranged, can not reduce the standard will be used. A moment of convenience or luck now will inevitably make the later work pay a heavy price and energy.