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RFID Membuat Pencatatan Waktu Tidak Menyakiti di Situs Konstruksi

Otomatisasi; itu adalah teknologi modern hari ini!

Melacak Waktu Konstruksi
Melacak Waktu Konstruksi

Recently, Telaeris was asked to simplify employee time-keeping for a construction yard using radio frequency identification (RFID) technology. The company had 3000 employees and wanted to know both who was on the job site and when they came and left. Instead of hand punched time-cards which were tedious and error-prone, we provided them with an elegant, effective, and most importantly, automated solution. Here’s how it worked:

First, an RFID tag was placed on each employee hard-hat.

Selanjutnya, kami menempatkan dua antena RFID UHF jarak jauh di setiap gerbang. Ketika setiap karyawan melewati gerbang dan antena, pembaca menangkap informasi arah dan tag karyawan.

Akhirnya, semua data ini secara otomatis dimasukkan ke dalam kami Sistem XPressEntry dan basis data. Kami melacak setiap entri karyawan dan keluar setiap hari untuk menghitung waktu harian mereka. Tetapi yang lebih penting, kami terus mencatat siapa saja yang ada di lokasi, jadi dalam keadaan darurat, majikan langsung tahu siapa yang bertugas, meningkatkan keselamatan karyawan.

Itu dia!

It’s nice to have a system function so straightforwardly, but there are many factors which we had to consider for this project. Below is a in-depth explanation of the RFID technology behind it and what we based our choices on.

Tag RFID

When deciding on the tag placement and tag type for any situation, it is important to keep a few
faktor dalam pikiran:

Gunakan Case Environment: Dalam aplikasi pelanggan ini, tag itu akan secara teratur terkena unsur-unsur - khususnya matahari dan hujan. Itu harus cukup kasar untuk bertahan lama.

Daya Tahan Tag yang Diperlukan: Karena ini untuk perusahaan konstruksi, kami tahu bahwa label ini akan terkena kotoran, debu, dan minyak setiap hari. Selain itu, kami berharap dengan kerja keras yang dilakukan para karyawan, tag-tag itu bisa terbentur sedikit.

Tag Slimflex HID
Tag Slimflex HID

Persyaratan Mounting: Some customers are able to wear UHF cards in lanyards or have tags on wristbands for tracking their people. This customer wanted to have the tag affixed to the employee hard hat without modifying the helmet as this could damage the integrity of the helmet’s safety performance. This required a tag that was flexible enough to conform to the curved helmet and a strong adhesive that would hold it indefinitely.

Penempatan Lokasi Tag: We considered placing the tag on the inside of the hat to keep it more protected. However, an interesting fact about RFID tags is when they are too close to a human body, they become ineffective. Water, which makes up 60% of our bodies, absorbs RF energy. Having a tag placed on the inside of the hat near the back of the head, would likely decrease the tag read range. To improve the tag performance, we chose to place the tag on outside back of the hard hat. While this would leave it more exposed, it would provide more reliable tag readability. This location had the additional benefit of allowing us to better differentiate between entries and exits, by appropriate placement of the antennas.

Untuk memenuhi persyaratan kami, kami memilih tag dari garis HID SlimFex dari tag UHF. Tag ini fleksibel dan tahan lama, dengan karakteristik baca yang hebat.

Antena

Mirip dengan memilih tag, ada beberapa pertimbangan yang harus dibuat ketika memutuskan karakteristik antena, polarisasi, jumlah dan penempatan antena.

karakteristik: Kami perlu memeriksa penguatan antena dan lebar pancaran. Gain adalah kekuatan relatif dari energi yang dapat ditransmisikan antena. Lebar pancaran menggambarkan area di mana antena dapat membaca tag. Kedua faktor tersebut terkait dengan jarak suatu tag yang dapat dibaca dari antena. Menentukan gain dan lebar pancaran yang diperlukan untuk aplikasi dapat menjadi perbedaan antara keberhasilan dan kegagalan dalam instalasi. Misalnya, jika Anda mencoba melacak seseorang sebagai

Beamwidth dan Gain
Beamwidth dan Gain

mereka melewati pintu, tetapi tidak ingin membacanya melalui dinding, Anda akan menginginkan lebar balok lebar dan keuntungan sedang. Untuk aplikasi kendaraan, gain tinggi dan lebar berkas sempit lebih mungkin diinginkan.

Polarisasi: Selanjutnya yang perlu dipertimbangkan adalah polarisasi antena. Antena pasif UHF RFID dapat terpolarisasi secara sirkuler atau linier. Antena terpolarisasi linier mengirim frekuensi radio (RF) gelombang dalam satu bidang, yang memungkinkan mereka untuk membaca tag yang benar berorientasi keluar lebih lanjut. Antena polarisasi sirkuler kurang dipengaruhi oleh orientasi tag, tetapi memiliki rentang maksimum yang lebih pendek.

If you can’t consistently predict the orientation or height of the tag, then a circular antenna will more reliably read your tag, albeit with a shorter range. In the case of the tag on the helmet, we know both the approximate height and orientation of the tag, so a linear antenna gave us the best performance. But given the short distance requirements, both types gave more than satisfactory read range.

polarisasi
Linear vs Antena Polartized melingkar (sumber www.ti.com)

Jumlah dan Penempatan: Finally, we need to decide how many antennas are necessary for the job and how to place them at each entry/exit location. As a rough estimate, a circularly polarized antenna covers an 8 foot by 8 foot area at a range of 8 feet from the reader. Figuring out the number of antennas needed then depends the math of your area to cover. More overlap will provide better likelihood of not missing a tag as it passes by. Additionally, the entry and exit antennas needed to be far enough away so that they don’t conflict with each other, but close enough so that no area in the passageway fell out of range. For our scenario, there are 2 drive through portals and 2 walk through portals. For the 10-12 foot wide drive through portals, we used 4 antennas, 2 on each side of the driveway. For the smaller 4-5 foot wide walk through portals, we only needed 2 total antennas, with 1 antenna on each side.

That about wraps it all up! We are very excited about this project and can’t wait to see how much it will improve the everyday lives of the employees who will be using it!

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9123 Chesapeake Dr.
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