Fara da RFID

Tsarin UHF RFID yana da sassa uku: mai karatu, eriya ɗaya ko fiye, da alamomi. Mai karatu yana samar da siginar rediyo ta 920–925 MHz kuma yana aika ta eriya. Lokacin da alamar wucewa ta shiga filin eriya, yana girbi makamashi daga igiyar rediyo don ƙarfin ƙaramin microchip ɗin sa (yawanci yana buƙatar kawai ~10 microwatts). Sa'an nan kuma guntu yana canza siginar da ke shigowa kuma ya mayar da ita. ainihin nuna sigar da aka gyara baya. Wannan siginar da aka nuna tana ɗaukar lambar samfurin lantarki na musamman (EPC) na alamar.

Duk zagayen karatu. daga watsa tambayar zuwa karɓar amsar alamar. yana ɗaukar kusan millise seconds 1–3. Wannan shine abin da ke ba da damar mai karatu guda ɗaya don yin lissafin alamomi 200+ a sakan ɗaya ta amfani da tsarin rigakafin karo na EPC Gen2. Asarar siginar zagaye yana da mahimmanci (-40 zuwa -80 dB), wanda shine dalilin da ya sa ikon TX na mai karatu (yawanci 30 dBm / 1 watt) da kuma hankalin guntuwar alama (har zuwa -22 dBm) irin waɗannan takamaiman bayanai ne masu mahimmanci.

RFID ya mamaye nau'ikan mitar da yawa, amma UHF (860–960 MHz) ya mamaye aikace-aikacen kasuwanci saboda yana ba da mafi kyawun daidaito na kewayon karatu, gudu, da farashin alama. LF (125 kHz) yana karanta a cikin 10cm a ~1 alama/sec. mai kyau don bin diddigin dabbobi amma yana da jinkiri don kayan aiki. HF/NFC (13.56 MHz) ya kai ~1m a ~50 tags/sec. babba don biyan kuɗi da katunan shiga. UHF ya kai mita 1–12+ a 200+ tags/sec. manufa don samar da sarkar, dillali, da bin diddigin kadara.

A cikin ƙungiyar Vietnam 920–925 MHz, masu karatu suna amfani da Frequency Hopping Spread Spectrum (FHSS) a cikin tashoshi da yawa. Tsarin shine: mitar = 920.0 + (channel_index × 0.5) MHz. Tsarin da aka saba amfani da shi yana amfani da tashoshi 6 [0, 2, 4, 6, 8, 10] wanda ya kai 920.0 zuwa 925.0 MHz don iyakar rabuwar tashar.

Channel Index → Frequency (MHz)   Formula: f = 920.0 + (idx × 0.5)

Ch 0  → 920.0    Ch 4  → 922.0    Ch 8  → 924.0
Ch 1  → 920.5    Ch 5  → 922.5    Ch 9  → 924.5
Ch 2  → 921.0    Ch 6  → 923.0    Ch 10 → 925.0
Ch 3  → 921.5    Ch 7  → 923.5

Typical: use [0, 2, 4, 6, 8, 10] for max channel separation

Kowane alamar UHF RFID yana da mahimman abubuwa guda biyu: tsarin eriya (etched ko buga aluminum akan PET substrate) da microchip (IC). Eriya tana kama siginar mai karatu kuma guntu yana sarrafa umarni kuma yana mayar da bayanai. Hankalin guntu shine mafi ƙarancin ƙarfin da guntu ke buƙatar kunnawa. guntu da aka ƙididdige a -22.1 dBm na iya farkawa da kawai ~6.3 microwatts. Ƙananan (mafi korau) = mafi kyawun hankali = mafi tsayin kewayon karatu.

Iyalai na guntu gama gari sun haɗa da: NXP UCODE 9 (-22.1 dBm, 128-bit EPC, babu ƙwaƙwalwar mai amfani. ya mamaye a cikin dillali), Impinj M700 series (-22.1 dBm, 128-bit EPC. mai ƙarfi a cikin kayan aiki), da Quanray QStar-7U (-21.0 dBm, 128-bit EPC, 512-bit ƙwaƙwalwar mai amfani. manufa lokacin da kuke buƙatar adana bayanai kai tsaye akan alamar).

Abubuwan da aka tsara na alama: Dry Inlays (raw tag akan PET, ¢3–8, don canzawa zuwa lakabi), Wet Inlays (tare da manne, ¢5–12, shirye don amfani), Sticker Labels (bugawa, ¢8–25, tare da alama), Hard Tags ($1–15, ruggedized don yanayi mai tsauri), da lakabin Woven/Fabric (¢15–40, da aka dinka cikin tufafi). Nextwaves yana kera busassun inlays daga 35×17mm zuwa 95×8mm da lakabin sitika a cikin girman daidai.

EPCglobal Gen2 (ISO 18000-6C) yana gudanar da yadda masu karanta UHF ke sadarwa tare da alamomi. Babban abin da aka kirkira shine algorithm na anti-collision na slotted-ALOHA wanda ke barin mai karatu ɗaya ya ƙididdige ɗaruruwan alamomi a lokaci guda ba tare da sun tsoma baki da juna ba.

Ga yadda zagaye na ƙididdiga ke aiki: Mai karatu yana aika Tambaya tare da sigar Q (ƙirƙirar ramukan lokaci 2^Q). Kowane alama yana ɗaukar ramin bazuwar kuma yana jira. Lokacin da ramin alama ya isa, yana amsawa da lambar bazuwar 16-bit. Idan alama ɗaya kawai ta amsa, mai karatu ACKs kuma ya karɓi cikakken EPC. Idan alamomi da yawa sun yi karo, mai karatu yana tsallake wannan ramin. Bayan duk ramukan, Q an daidaita. sama idan karo da yawa, ƙasa idan ramukan da yawa fanko. kuma zagaye ya maimaita.

Saitunan Q masu amfani: Q=2 (ramuka 4) don alamomi 1–5, Q=4 (ramuka 16) don alamomi 5–20, Q=5 (ramuka 32) don alamomi 20–100, Q=6 (ramuka 64) don alamomi 100–500, Q=7 (ramuka 128) don alamomi 500+. Babban Q yana nufin ƙarancin karo amma zagaye a hankali.

Ci gaba na zaman yana sarrafa tsawon lokacin da alama ke tunawa cewa an riga an karanta ta. Zama S0 yana sake saiti nan take (don ci gaba da sa ido). S1 yana dawwama 0.5–5 seconds (daidaitaccen ƙididdiga). S2/S3 yana dawwama ≥2 seconds (ƙofofin tashar jiragen ruwa da na'urorin jigilar kaya inda kuke son a ƙidaya kowace alama sau ɗaya a kowane wucewa). Dokar babban yatsa: yi amfani da S0 don sa ido na shiryayye, S2/S3 don tashoshi.

Tag Count → Q Value → Slots → Use Case

  1-5       Q=2       4       fast, low overhead
  5-20      Q=4       16      good balance
  20-100    Q=5       32      warehouse shelves
  100-500   Q=6       64      pallet scanning
  500+      Q=7       128     dock doors, bulk

Higher Q = fewer collisions but slower rounds

Kowane alamar Gen2 yana da bankunan ƙwaƙwalwar ajiya 4. An tanada (Bank 00): Kalmar wucewa ta kashe + Kalmar wucewa ta shiga, jimlar bits 64. EPC (Bank 01): CRC-16 + Kalmar Sarrafa Yarjejeniya + mai ganowa EPC ɗin ku, yawanci 96–128 bits. TID (Bank 10): Masana'anta-ƙone na musamman ID na guntu wanda ba za a iya canzawa ba. mai mahimmanci don yaƙar ƙirƙira. Mai amfani (Bank 11): Zaɓin adana bayanai na al'ada (0 zuwa 512+ bits dangane da guntu), mai amfani don lambobin batch, kwanakin dubawa, ko bayanan firikwensin.

Lokacin da mai karatu ya yi lissafin alamomi, kowane sanarwa ya ƙunshi: ID na eriya (wace tashar jiragen ruwa), ƙimar RSSI raw (0–255, canzawa zuwa dBm ta hanyar: dBm = -100 + zagaye (raw × 70 / 255)), bayanan EPC (bytes 12+), da fihirisar tashar mitar. Wannan bayanan shine abin da aikace-aikacenku ke aiwatarwa don taswirar karatu na alama na zahiri zuwa abubuwan kasuwanci kamar 'abu da aka jigilar' ko 'pallet da aka karɓa'.

[ANT] [RSSI] [EPC ×12 bytes ..................] [CH]
 01    B4     30 34 25 7B F7 19 4E 40 00 00 1A 85  06

Antenna:  1 (port 1)
RSSI:     180 → dBm = -100 + round((180×70)/255) = -51 dBm
EPC:      3034257BF7194E4000001A85 (SGTIN-96)
Channel:  6 → 920.0 + (6×0.5) = 923.0 MHz
GTIN-14:  80614141123458  Serial: 6789

Ga jerin abubuwan da za a yi amfani da su don saita tsarin RFID na farko, tare da takamaiman jagora a kowane mataki.

Input:  GTIN-14=08600000232451  Serial=1001  Prefix=7 digits
Output: 30 14 1A 80 0E 98 78 00 00 00 03 E9  (12 bytes)