product information Elapsed time indicator ET2020/EFA G G G G G G G features EEPROM non-volatile memory 10 years data retention Low power, 10 mW typical Serial and parallel outputs Micro processor compatible Non-volatile text storage and recall Military specifications description application diagrams The 18 pin ceramic dual-in-line elapsed time indicator (ETI) is assembled using hybrid technology, ensuring suitability for applications where severe environmental conditions maybe encountered. Typical serial and parallel application diagrams are shown below. The internal timer is activated whenever the 5V power supply is applied. No additional timing control circuitry is required. parallel mode The total elapsed time is accumulated in the internal non-volatile memory for interrogation through the serial or parallel interfaces. serial mode VAUX dimensions pin assignment VAUX TX RX Test pin (8) is for factory purposes and should be left unconnected product information serial data (output select = 0) characteristics Operating temperature range Storage temperature range Supply voltage VCC Supply voltage VAUX Supply current Timing resolution Timing accuracy Capacity (parallel mode) Capacity (serial mode) Pulse count frequency Pulse width VOH output logic 1 VOL output logic 0 VIH input logic 1 VIL input logic 0 IZ high Z leakage current -55 to 125C -55 to 125C 4.5 to 5.5 Vdc 4.0 to 5.5 Vdc 1mA typical, 2mA max 0.01 hours 0.1% 104 hours/106 pulses 105 hours/107 pulses 30 Hz max 10ms min VCC -1 to VCC VSS to 0.2 x VCC 0.8 x VCC to VCC VSS to 0.2 x VCC 10A Serial data transfer uses two pins, Rx (receive data) and Tx (transmit data). Together with a signal common, these lines constitute a 3 wire serial communication interface utilising a standard non-return to zero (NRZ), data format. Direct interface can be made with integrated circuit UART devices. The signals can also be level shifted to conform to RS232 requirements. The Rx and Tx signals must meet the following requirements: 1 A High level indicates logic 1 (5V) and a low level indicates logic 0 (0V) 2 The Rx input must be a high state prior to reception of data 3 A start bit, (logic 0), is transmitted/received indicating the start of a message interrogation 4 Bytes of data are transmitted/received least significant bit first ETIs can be interrogated via serial or parallel format. The output select (OS) input is used for selection of interrogation mode. 5 A stop bit, (logic 1), in the 10th bit position indicates transmission/reception of a byte is complete serial elapsed time 6 Baud rate: Data bits: Start bits: Stop bits: Parity: 9600b/s 8 1 1 none To initiate transmission of serial elapsed time/pulse count data a unique two character ASCII command "ET" must be received at the Rx input. Following reception of a valid "ET" command the ETI will output the elapsed time message on the Tx output. If an invalid command is received an ASCII carriage return character, (0D hex), is transmitted. byte 1 2 3 4 5 6 7 8 9 character cr 0 0 0 0 0 . 0 0 hex 30 30 30 30 30 2E 30 30 0D Bytes 1 and 12 are ASCII carriage return characters. Bytes 2 to 9 represent the elapsed time reading and are ASCII characters. Byte 2 is the most significant digit. Byte 7 is always "." and byte 11 "H" denoting units of hours. Elapsed time measurement is suspended for typically 300 ms during serial data output. 10 20 11 12 H cr 48 0D product information parallel data (output select = 1) Parallel elapsed time/pulse count interrogation is initiated by holding the request time input at logic 0 for time tRT or until the positive edge of DV(1). The elapsed time/pulse count then appears sequentially in 3 bytes on outputs D0-D7. Data is synchronised with pulses which appear on the data valid (DV) output. Each byte represents a 2 digit BCD number. Outputs D7-D4 represent the most significant digit, outputs D3-D0 represent the least significant digit. D0 - D7 are tri state outputs suitable for direct connection onto a high impedance data bus. power supply A single 5 volt power supply, Vcc is required for operation. A separate power supply input VAUX is also provided for energisation from a second power source. A blocking diode is internally connected to prevent current from VAUX powering parent equipment connected to Vcc. This provides cold read facilities during failure of parent equipment or when it is powered down. ID (mA) typical drive current graph Vcc - VOH (volts) BCD parallel output During DV(1) the digits represent HOURS x 103 and HOURS x 102 During DV(2) the digits represent HOURS x 101 and HOURS x 100 During DV(3) the digits represent HOURS x 10-1 and HOURS x 10-2 parameter description min tI initialisation time tRT request time pulse width for time information only 6 tRTT request time pulse width for time and text information 16 tSDV time to set up first data valid tDV data valid pulse width tPDV period of data valid tOT total bus active time tOET max units 600 ms 12 ms ms 6 ms 90 110 s 4.99 5.01 ms 264 ms total bus active time, elapsed time only output 15 ms tZDV time from end of Z state to first DV 175 typical s tDS data set up time 90 typical s tRTP request time repetition period 300 ms product information user programmable text text entry ordering information 50 bytes of EEPROM are provided for user entry and storage of 50 characters of text information. The text may record, for example maintenance and warranty status of parent equipment. Text may be rewritten as often as required and can be read by both serial and parallel outputs. Text can only be entered serially. Text entry can only be made whilst in serial mode and is initiated by detection of the ASCII "IX": command at the Rx input. Up to 50 ASCII text characters should then be input, terminated either by a carriage return or by entry of the 50th character. Text entered will overwrite previously stored text. Elapsed time indicator ET2020/EFA Non volatile pulse counter PC2020/EFA serial text input This product data also applies to the ET2020/EFA/01 variant qualification Originally approved to DEF-STAN 59-61 (Part 90/257) Company approvals: BS EN 9001:2000 (FM 01759) BS EN ISO 14001:2004 (EMS 60559) AS EN 9100 REV B Oxley Developments Company Ltd serial text interrogation Serial text interrogation is achieved by using the ASCII "OX" command. Serial Text Output Priory Park Ulverston Cumbria LA12 9QG United Kingdom t: +44 (0) 1229 483226 f: +44 (0) 1229 580687 e: sales@oxley.co.uk Oxley Inc 31 Business Park Drive Branford CT 06405 USA parallel text interrogation Parallel text interrogation is initiated by holding the request time input at logic 0 for the time tRTT or until the positive edge of DV(4). Following the 3 bytes of elapsed time/pulse count information, the ASCII text appears on outputs D0-D7 synchronised with data valid pulses DV(4) to DV(53). To request elapsed time information only, the request time pulse width should not exceed tRT max. Elapsed time t: +1 (203) 488-1033 f: +1 (203) 481-6971 e: sales@oxleyinc.com Oxley Group Australia Pty Ltd PO Box 24 Artarmon NSW 1570 Australia t: +61 (0) 2 9460 9112 f: +61 (0) 2 9460 9114 e: sales@oxleyaustralia.com w: www.oxleygroup.com measurement is suspended for typically 300ms during parallel data output. (c) Oxley Developments Company Ltd 2008 ODCSM40681/2/08