The RFID, Inc. Model 2022 and 2022E (enclosed version) are Serial Multiplex Interfaces designed for use with RFID, Inc. RF Electronic Labels (Tags) and compatible Readers (Models 1845 and 1885). The device acts as a bridge, converting RF signals from Tags detected by Readers into a serial data stream for a host computer or terminal.
Function Description:
The Model 2022 Interface is termed "Multiplex" because it can manage up to 16 addressable Readers and Antennas using time-division multiplexing. It provides a full-duplex, asynchronous bit serial data stream compatible with RS-232-C, RS-422-A, or RS-423-A specifications, configured as Data Terminal Equipment (DTE). The primary functions include:
- Signal Monitoring: It monitors SIGNAL inputs from Readers for the presence of Electronic Tag data.
- Reader Control: It generates ENABLE pulses to control Readers, ensuring only one is enabled at any given time. The Interface first issues a RESET pulse to disable all Readers, then follows with INCREMENT pulses to enable each Reader sequentially. During the brief period each Reader is enabled, SIGNAL inputs are monitored for Tags. If a Tag is detected, its contents are reported along with a hexadecimal channel number identifying the Reader. A READ pulse is generated upon Tag detection, which also increments the active Reader.
- Serial Communication: It communicates with a host computer over a serial interface, transmitting Tag data and receiving commands. All messages are transmitted in printable ASCII characters in either transmit-on-receipt or polled mode. Advanced error detection algorithms ensure reliable operation.
Via the serial connection, the Interface can be commanded to buffer Tags, report multiple Tag readings, repeat the last message, test itself, reset, or delete specified Readers from its polling loop.
Important Technical Specifications:
- Protocol: Full-duplex, RS232/423 or RS422. Selectable stop bits, parity sense, and word length.
- Serial Data Rate: Selectable baud rates: 110, 300, 600, 1200, 2400, 4800, 9600, 19200.
- Control Signals: DSR, CTS, DTR.
- Processing Speed: Up to 20 Readings/second.
- Data Storage: 2 Readings (buffered).
- Error Rate: Less than 1 in 10 to the 14th readings.
- Connectors:
- Serial: DB-25S.
- Power: 64-pin DIN 41612 Type C.
- Readers: 5 position screw type terminal strip.
- Multiplex Control: 2-wire, Multi-drop scheme, 48mA, max.
- Input: 75 Ohms, Balanced, Multi-drop.
- Cabling Distance to Readers: Up to 5000 feet, total (with shielded twisted pair cable).
- Power Requirements: +5 Volts DC, +/- 5% @ 350 mA. (max.) 250 mA. (typ.).
- Temperature Range:
- Operating: -40 to +70 degrees C.
- Non-operating: -55 to +85 degrees C.
- Dimensions:
- Model 2022: 7.0" x 3.9" x 6.6".
- Model 2022E: 9.0" x 5.1" x 1.7".
- Weight:
- Model 2022: 5.5 oz.
- Model 2022E: 1.24 lbs (.56kg).
Usage Features:
- Installation: The Eurocard format and single supply voltage simplify integration. Connections to Readers use low-cost shielded twisted pair cables and angle entry terminals.
- Power Connection: Power is supplied via a 64-pin DIN connector (P1). For the Model 2022E, power wiring is pre-threaded through a cable gland. An external fuse is recommended as there is no onboard overcurrent protection.
- Reader Wiring: Shielded, #14 to #28 AWG, insulated, stranded wire is recommended for signal and enable wiring, especially for long lengths or high electromagnetic noise environments. Shields should be connected at only one point, typically at the Reader for SIGNAL wires and at the Interface for ENABLE wires.
- Serial Communication Configuration: Communication characteristics (speed, parity, stop bits, data bits) are set using jumpers on PCB addresses P3 and P4.
- Serial Type (RS-232/RS-422): Jumper on P4 selects between RS-232 (center and right-most pins) or RS-422 (center and left-most pins).
- Word Format (Data Bits, Stop Bits, Parity): Jumpers on P3 (7B, 2S, EV, ON) configure data bits (7 or 8), stop bits (1 or 2), and parity (Even/Odd, On/Off).
- Baud Rate: Bottom three jumpers on P3 (B2, B1, B0) select baud rates from 110 to 19200.
- Serial Cabling: Connects to the host via a 25-pin, female "D" connector (P2). The Interface is configured as DTE, transmitting on pin 2 and receiving on pin 3. Modem eliminators or gender changers may be required depending on the host's configuration.
- Operating Modes:
- Mode #1 (Single Report, Transfer on Receipt): Default if M2 jumper is off. Interface scans for Tags and transmits data immediately upon detection, once.
- Mode #2 (Polled Operation): Default if M2 jumper is on. Interface scans for Tags, stores data (up to two Tags buffered), and transmits upon host request via the Transfer Request command [T].
- Mode #3 (Report Duplicate Tags): Selected via software command [M3]. Interface continually scans and repeatedly transmits Tag information as long as a Tag is detected in the Reader's signal field. Exit only via System Reset or power cycling.
- Commands: All commands are issued in CAPS, preceded by a Beginning of Message (BOM) delimiter ( or [) and followed by an End of Message (EOM) delimiter ( or ]).
- [I] INITIATE SELF TEST: Performs a comprehensive self-test, displays firmware version, and reports success/failure of internal components.
- [A####] ASSIGN READERS: Instructs the Interface to include or exclude specific Readers from its polling loop using a 4-hexadecimal digit binary bit map. [A0000] stops Reader control pulses and Tag searching.
- [M#] MODE CONTROL: Switches between operating modes (M1, M2, M3).
- [B####] BUFFER RESET: Allows re-reporting of previously detected Tags without a two-second removal. [BFFFF] resets all 16 Reader buffers. [B0000] clears the Mode 2 Tag transfer buffer.
- [T] TRANSFER REQUEST: Used in Mode 2 to request transmission of a single buffered Tag's data.
- [R] REPEAT MESSAGE: Repeats the previous transmitted message, useful if the host detects transmission errors.
- [K####] SET ACCESS KEY: Causes the Interface to recognize only Tags programmed with a matching 4-digit access key, used for security and access control. Default is FFFF.
- [S] SYSTEM RESET: Performs a software reset, reverting to default settings, enabling all Readers, setting access key to FFFF, and issuing a power-up message.
- Tag Data Format: Tags report as
<LF># xxxxxxxxxxxxxxxx<CR>, where # is the Reader address and xxxxxxxxxxxxxxxx is the 16-character Tag data (or 8 characters for Model 2022/8).
- Auxiliary Port: An 8-bit parallel auxiliary port (pins c22-c31 on P1) can drive an LCD Display. If unused, pins should be left open.
Maintenance Features:
- Self-Test: The [I] command allows for a comprehensive self-test, reporting on ACIA, RAM, ROM, and timer functionality. This helps diagnose internal issues.
- Watchdog Timer: The system includes a WATCHDOG circuit that automatically resets the microprocessor if it becomes unresponsive due to power surges or failures, ensuring continuous operation.
- Error Messages: The Interface provides clear error messages:
r - Repeat Last Transmission: Indicates a transmission error on the last command.? - Invalid Command: Indicates a problem with the last command issued (e.g., illegal delimiter, unknown command, invalid command for current mode).e - Empty Buffer: Issued in Mode 2 when a Transfer Request is made but no Tag is buffered, or in Mode 1 if a Repeat Message command is received after the last Tag has been replaced.
- Firmware Updates: The self-test reports the firmware release version, which is useful for support and potential updates.
- Warranty: RFID, Inc. products are warranted against defects in materials and workmanship for one year from the date of shipment. This includes repair or replacement at RFID, Inc.'s plant. The warranty does not cover defects from abuse, misuse, accident, alteration, neglect, or unauthorized repair. The company disclaims implied warranties of merchantability and fitness for a particular purpose.
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