UHF in time attendance and access control systems


    As a rule, the time and access control systems offered on the market have a number of disadvantages that are problematic to solve: transferring cards to other employees, confusion between the choice of arrival / departure modes, and the accumulation of a large number of personnel at checkpoints and accounting points. Terminals with biometric automation technologies solve problems only partially. At the same time, companies do not have legal force obliging an employee to register their biometric data in the terminal. In this article, we will try to get around these problems by creating a system for recording time and access control using UHF RFID technologies and devices based on the Tibbo Project System hardware platform.. First of all, the information will be useful to automation and integrators.

    We already wrote about the terminal developed by us accounting for working hours on the platform TPS . Summing up the previous article: a terminal was created with an Ethernet interface (optional Wi-Fi), external identification devices, a display, built-in relays (optional), network or offline mode of operation. Connecting one or two external readers allows you to configure the device in the access controller mode. The solution integrates with our 1C processing and professional AggreGate Time & Attendance software , and open source firmware and TPS hardware modularityAbsolute flexibility in deploying the system.

    But when installing the system on real objects, we ran into problems that, despite the apparent simplicity, still cannot be solved by equipment manufacturers using trivial methods. We list some of them:

    • The employee needs to stop at the point of entry (accounting) to register the arrival / departure event . In small companies, this does not cause great inconvenience. But at large facilities (factories, business centers, etc.), with the number of employees of several hundred or even thousands of people, this translates into serious problems: “crush” at the checkpoint, line, etc. Various schemes offer a solution, one of which is the “diversity” of work shifts in time. But not in any situation, such schemes are applicable and convenient.
    • To account for working hours, the terminals require manual entry of the type of event (arrival / departure) by pressing a button. Users constantly forget about this, which leads to errors in the subsequent calculation of hours worked. As a solution, terminals with auto-inclusion of the type of event in time are offered. For example, at 8.00 the terminal automatically switches to the “arrival” mode, and at 16.00 to the “departure” mode. But the urgency of the problem does not disappear for employees who can visit the office at different times of the day, for example, sales managers.
    • Tracking lunches, breaks, breaks. Some terminals allow you to record events of temporary outputs. But getting employees to use this feature is problematic. As a solution, an electromagnetic lock is connected to the terminal by controlling the access point (the employee cannot exit without fixing the event). But at the same time, discipline is violated by a “multiple” exit. Those. several employees leave the room, but one of them fixes the event, reducing the number of “not worked” hours per person.
    • Card transfer. No one bothers the company’s staff to leave the card on the desktop, and in the morning, being late for work, ask colleagues to “check out”. One of the solutions to this problem is the introduction of biometric readers. But, not counting the cost, there is a serious obstacle to their implementation. A citizen of the Russian Federation cannot oblige to register their fingerprints or other biometric data, as it affects constitutional rights. Cases requiring the delivery of fingerprints are described in the relevant federal law (N 128-FZ of July 25, 1998). In other words, the employee has the right to refuse to use the fingerprint terminal. If the employee does not mind, the employer must take written confirmation of this. In addition, biometric readers do not exclude the previous problems described.


    We have used UHF technology to automate time tracking . This approach allowed to bypass, if not all, then many of the problems that arise. The principle of operation of the terminal does not differ from the classical version: reading the identifier, fixing the type of event arrival / departure, setting the date / time field, sending information to the server (or storing in the internal memory until the request). If necessary, the relay response algorithm is configured, and access control functionality is integrated . All logic for processing primary data is executed on the server.

    Features relate to the principle of operation of the reader UHF (Ultra High Frequency) . The technology allows you to scan passive RFID tagswithin a radius of several meters to several tens of meters. As a rule, readers give a good result in scanning time: from several tens to several hundred marks per second. These features allow the use of UHF technology in tasks where high and low frequency RFID standards could not be applied: inventory, retail, logistics, etc.

    In the proposed version of the time tracking system using UHF technology, the reader itself is located in a hidden place. Antennas (which actually read the label) are mounted on top and there are two of them: one on the outside of the access point, the other on the inside. The antenna power and range are adjusted during installation on the object and depend on its geometric parameters. The reader connects to the terminal on the TPS, which can also be hidden in an invisible place, because There is no need to visualize information. In fact, the terminal turns into a controller. The working scheme is simple: the user is given a badge with a UHF tag. When crossing the access point, the badge is sequentially read by two antennas. The reading order determines the type of event (arrival / departure). The logic is simple, what are its advantages?

    The employee does not linger at the point of entry. It simply passes by, and the system records the arrival event without creating a queue and a “flea market”. This eliminates the error when the employee selects the wrong type of event (instead of “leaving”, he activates the “arrival”). Having fixed the order in which tags are read by antennas, the controller on the TPS automatically determines the type of event. If users are obligated to constantly have badges with them, the system receives more primary information. There is an opportunity to track breaks, the time spent by an employee in a particular office cabinet (subject to automation). And this information provides the basis for a more detailed examination of the staff’s working day.

    Thus, three of the four problems listed above are closed. However, there remains a serious drawback: how to oblige an employee to always have a badge with him and exclude the possibility of transferring it? This can be achieved using the access control function embedded in the terminal on the TPS. When reading the label with the first antenna, the device checks the validity of the badge in the database. If the result is positive, the door lock is unlocked, but the event is not recorded (in case the employee passed by, but fell into the field of action of the antenna). When crossing the zone of the second antenna, the corresponding type of event is recorded. Thus, it is difficult to transfer cards among staff.

    For greater certainty, you can complicate the circuit by adding photocells or IR passage detectors. These elements (used in visitor counting devices) count the number of people crossing the passage point. Detectors are connected to the TPS terminal by elementary installation of the corresponding tibbit. The logic of the operation is simple: if an entry (exit) event of one badge is identified, but at the same time the beam intersects more than once, the system generates a record with a warning label. The record shall indicate the identifier of the card, room, date / time and the number of beam intersections (in other words, the number of people actually traveled). At the end of the reporting period, it will become clear who tried to go on one card for a break. At the same time, a reasonable question arises - what about the guests, partners and customers whom the company employee meets? This is another reason to fill in the CRM system with the meeting results in time. In practice, it is unlikely that anyone will pay attention to isolated cases. If a similar situation occurs daily in the department, there will be a reason to conduct an audit.

    Deploying such a system is not a cheap pleasure, so the solution is unlikely to suit small offices. However, in the automation of large companies (from several hundred people), the system is able to quickly pay for itself. With an average “fine” of an employee (we can talk not only about fines, but also about an agreement on an hourly payment) of about 100 rubles a month, we can calculate that the company saves from several tens of thousands per month. The total cost of the system depends on the number of access points for automation, the requirement for integration with other subsystems, etc. However, it is safe to say that payback occurs at a very reasonable time (up to 1.5 years).

    The second application is the automation of business centers. The developer or landlord installs the system on a common entrance, on floors and, if necessary, with a deeper detail of the premises, deploys its own server. Further, ready-made reports or primary data on attendance and movement of employees are provided to tenants for a set fee.

    It is also worth paying attention to the fact that the principle of operation of the reader, terminal, features of the technical installation and the primary data provided by the system almost completely meet the requirements for the automation of some logistics processes (for example, tracking the movement of tangible assets), which allows integrators to find a different market for the application of announced technologies .

    If you are interested in a solution, contact our staff to discuss project details.

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