This document provides additional detail of the AUTOIMET system functions, with brief descriptions of each PC board and discussion of options. For more information on operation and technical details, refer to the AUTOIMET Documents CDROM.
The AUTOIMET Main Electronics consists of a two-board set of CPU and interface which handles the power and comms to the individual ASIMET modules as well as optional PTT or internal barometer or internal A/D board. All MET modules are sampled at the start of each logging interval (set by RI parameter in UOK command). All the "live" interval data is available via the 'D' and 'E' commands on the primary RS232 "console" interface used for all AUTOIMET communications.
The AUTOIMET CPU board is based on a Dallas Semiconductor DS87C530 microcontroller. DS87C530 internal peripherals include a real time clock and 2 uarts; 2 additional uarts are included on the CPU board as well. Also present on the CPU board is a PCMCIA interface for the 20MB FLASH memory card included with the system; at a 1-minute logging interval, there is enough storage for over 400 days of data. A standard CR2032 lithium coin cell provides battery-backup for the realtime clock. Operating parameters are stored in EEPROM and are NOT dependent on the backup battery. A normally unused RS485 console interface at P1 is also present on this board.
(To use RS485 comms with the AUTOIMET logger, kill power, swap AUTOIMET CPU board jumper JP1 to 2-3 [indicated by a small white dash on the silkscreen], remove the POWER/COMMS cable from the LOGR53IF P12 connector, and attach it to P1 on the AUTOIMET CPU. At power up, no sign-on message will be sent, but all commands will function as in RS232 mode. Note that the XMODE command will only send a brief message "XMODEM data dump requires RS232".)
The LOGR53IF Interface board handles power and comms distribution to the ASIMET modules as well as interface to various options such as local GPS or A/D modules. Connector P12 is the main RS232 "console" interface to the AUTOIMET and can also be used to apply external power (up to about 100 MA) to the system during test. The main +12-15V battery stack (for the base logger with FLASH card) is connected to P13; the "sensor" +12-15V battery stack (which typically powers the ASIMET modules) is connected to P14; the "aux" battery stack (which typically powers the optional PTT) is connected to P19. Regulated +5V power for the system is produced on this board.
It is recommended that main power for the logger be kept separate from either MET module power or GPS and other option power. Battery size should be estimated (based on typical current consumptions determined during testing) such that the logger at least continues to run til the last.