UHF in working time and access control systems

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

We have already written about the working time accounting terminal developed by us on the TPS platform . Summarizing 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 standalone 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 software AggreGate Time & Attendance , and the open source firmware and hardware modularity of TPS allow you to achieve absolute flexibility when deploying the system.

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

• The employee must stop at the point of entry (accounting) to register an arrival / departure event. In small companies, this does not cause much inconvenience. But at large sites (factories, business centers, etc.), with a number of employees of several hundred or even thousands of people, this translates into serious problems: "twitches" at the checkpoint, queues, etc. As a solution, various schemes are offered, one of which is the "separation" of work shifts in time. But not in any situation such schemes are applicable and convenient.
• To take into account the working time, the terminals require manual input of the event type (arrival / departure) by pressing a button. Users constantly forget about this, which leads to errors in the subsequent calculation of time worked. As a solution, terminals with auto-inclusion of the event type on time are offered. For example, at 8.00 the terminal automatically switches to the “arrival” mode, and at 16.00 in the “exit” mode. But the urgency of the problem does not disappear for employees who may visit the office at different times of the day, for example, sales managers.
• Tracking lunch, smoke breaks, breaks. Some terminals allow you to capture temporary exit events. But getting employees to use this feature is problematic. As a solution, an electromagnetic lock is connected to the terminal, controlling the point of passage (the employee cannot exit without registering an event). But at the same time, discipline is violated in a “multiple” way. Those. Several employees leave the premises, but the event records one of them, reducing the number of “not worked” hours per person.
• Transfer cards. 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 in”. One of the solutions to this problem is the introduction of biometric readers. But, apart from the cost, there is a serious obstacle to their implementation. Citizens of the Russian Federation cannot be obliged to register their fingerprints or other biometric data, since it affects constitutional rights. Cases obliging to submit fingerprint data are described in the relevant federal law (N 128- dated July 25, 1998). In other words, the employee has the right to refuse to use the fingerprint time attendance terminal . If the employee does not mind, the employer must obtain written confirmation of this. In addition, biometric readers do not exclude the previously described problems.

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We applied UHF technology to automate time tracking . This approach made it possible to circumvent, if not all, many of the problems that arise. The principle of operation of the terminal does not differ from the classic version: reading the identifier, fixing the type of the arrival / departure event, setting the date / time field, sending information to the server (or storing it in the internal memory before the request). If necessary, a relay triggering algorithm is set up, access control functionality is integrated. All the processing logic of the primary data is performed on the server.

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

In the proposed version of the system of accounting of working time using technology UHF, the reader itself is located in a hidden place. Antennas (which actually read the tag) are mounted on top and there are two of them: one on the outside of the aisle point, the other on the inside. The antenna power and range are adjusted when installed on an object and depend on its geometrical parameters. The reader is connected to the terminal on the TPS , which can also be hidden in an invisible place, since the need to visualize information is eliminated. In essence, the terminal turns into a controller. The scheme of work is simple: the user is issued a badge with a UHF tag. When crossing the point of passage, the badge is successively read by two antennas. The reading order determines the type of event (arrival / departure). The logic is simple, what advantages does it give?

The employee does not stay at the point of passage. He just passes by, and the system records the event of the parish, without creating a queue and "flea". This eliminates the error when the employee chooses the wrong type of event (instead of "leaving" activates the "arrival"). Having fixed the reading order of the tag with antennas, the controller on the TPS automatically determines the type of event. If users are required to constantly keep their badges with them, the system receives more primary information. It becomes possible to track breaks, the time the employee is in a particular office (if they are automated). And this information provides the basis for a more detailed consideration of the working day of staff.

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

For more confidence, you can complicate the circuit by adding photocells or IR pass detectors. These elements (used in counting devices) count the number of people crossing the point of passage. The connection of detectors to the TPS terminal is carried out by the elementary installation of the corresponding tibbit . The logic of operation is simple: if an entry (exit) event of a single badge is identified, but the beam intersects more than once, the system generates a record with a warning label. The entry indicates the card ID, location, date / time and the number of beam intersections (in other words, the number of people actually passed). At the end of the reporting period, it will become clear who tried to go through one card at a break. This raises a reasonable question - what about the guests, partners and customers who are met by an employee of the company? This is another reason to fill in the CRM system in time with the results of the meeting. In practice, it is unlikely that anyone will pay attention to isolated cases. If a similar situation occurs in the department every day, there will be a reason to conduct an inspection.

Deploying such a system is not a cheap pleasure, so the solution is unlikely to suit small offices. However, with 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 hourly payment contract) of about 100 rubles per month, you can calculate that the company saves 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 business center automation. The developer or landlord installs the system on a common gateway, on the floors and, if necessary, with a deeper specification of the premises, the own server is deployed. Further, ready-made reports or primary data of attendance and relocation of employees are provided to tenants for a set fee.

You should also pay attention to the fact that the principle of the reader, the terminal, technical installation features and the primary data provided by the system almost completely meet the requirements for automating some logistics processes (for example, tracking the movement of tangible assets), which allows integrators to find a different market for the use of sounded technologies .

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