WattNode Logger for LonWorks Programming Details

// The following structure defines the log information file. This is used by Neuron C to keep
// track of the current and oldest record number, Flash addresses, etc. This is preserved
// across power failures.
// 
// Note: the FTP file for this is defined as 64 bytes long, but we don't have 64 bytes of 
// content. Rather than waste RAM, we'll make this smaller and just zero pad the file or end
// the file early.
typedef struct {
  int32 CurrentRecNum;      // The most recent logged record number.
  TLogAddr CurrentRecAddr;  // The flash address of the most recently logged record
  SNVT_time_stamp CurrentRecDateTime;  // The timestamp of the most recent log record
 
  int32 OldestRecNum;       // The oldest log record number in the serial flash
  TLogAddr OldestRecAddr;   // The flash address of the oldest logged record
  SNVT_time_stamp OldestRecDateTime;   // The timestamp of the oldest log record
 
  uint16 crc;               // Every time we update this structure, compute the CRC
  uint8 logInitialized;     // Must be set to LOG_INIT_VALUE when the log is initialized
} TLogInfo;

// The TLogAddr structure is used to address locations in the serial flash 
// efficiently, since the flash uses a page/offset addressing scheme.
typedef struct {
  uint16 page;    // The page number ranges from 0..4095
  uint16 offset;  // The offset ranges from 0..527
} TLogAddr;
 
// This is the definition for the SNVT_time_stamp type, with the types
// modified to int16 and uint8.
typedef struct {
  int16 year;
  uint8 month;
  uint8 day;
  uint8 hour;
  uint8 minute;
  uint8 second;
} SNVT_time_stamp;

// The following struct defines the log retrieval setup file
typedef struct {
  // Note: not all fields are used. We could overlap fields, but unions are tough in VB6
  // so it's easier and clearer to provide non-overlapping fields and waste some space.
                                  // Byte#: Description
  uint8 retrievalType;            //     0: 0 = full (start with oldest record, stop on newest), 
                                  //        1 = prior-n (start with newest record, read 'count' records), 
                                  //        2 = to-date (start with newest record, stop on stopDateTime or
                                  //          after seven older records (in case of out-of-order records), 
                                  //        5 = to-recNum (start with newest record, stop on stopRecNum or
                                  //          after seven older records (in case of out-of-order records), 
  int32 count;                    //  1- 4: count of records to transfer
 
  int32 reserved1;                //  5- 8: reserved
  TLogAddr reserved2;             //  9-12: reserved
  SNVT_time_stamp reserved3;      // 13-19: reserved
 
  int32 stopRecNum;               // 20-23: ending record number
  TLogAddr reserved4;             // 24-27: reserved
  SNVT_time_stamp stopDateTime;   // 28-34: ending date/time
 
  uint8 reserved5;                //    35: reserved
  int32 reserved6;                // 36-39: reserved
  uint8 compressMode;             //    40: 2 = full (all logged fields), 
                                  //        3 = basic (date, time, EnergySum, demand, status)
 
  // The following fields are used internally in the WattNode meter to track the progress 
  // of active transfer. They are initialized when the log data file is opened. They could
  // be read out after a transfer if desired, but not during a log transfer.
  uint8 supportedSetup;  // 1 = supported transfer setup? If not, return EOF immediately.
  uint8 direction;       // 0 = current first (backwards), 1 = oldest first (forward)
  uint16 countLeft;      // Count of records left to transfer
  uint8 transferDone;    // Set to TRUE to terminate transfer
  TLogAddr recAddr;      // The address of the record to transfer
  uint8 recPos;          // The position within the record being transferred
  int32 recNum;             // current log record number
  SNVT_time_stamp dateTime; // current log date/time
} TLogSetup;

typedef struct {             // Byte#: Description
  uint8 logType;             //     0: This value is always 1
  int32 recordNum;           //   1-4: Unique log record number (>4000 years to overflow)
  TLogStatus logStatus;      //     5: Status event logging
  SNVT_time_stamp dateTime;  //  6-12: Date/time for log record (from WattNode nviTimeSet)
  uint16 logSeconds;         // 13-14: Number of measured seconds in this log interval
  float32 demand;            // 15-18: Most recent nvoDemand value
  int32 energySum;           // 19-22: Energy with 0.1 kWh resolution
  int8 crcA;                 //    23: Eight bit CRC on the first 23 bytes
  // 24 bytes: End of the short log records, the following are added for long records
  int32 energyPosSum;        // 24-27: Positive energy (0.1 kWh resolution)
  int32 energy[3];           // 28-39: Energies for phase A, B, and C (0.1 kWh resolution)
  int32 reacEngySum;         // 40-43: Reactive energy sum (0.1 kVARh resolution)
  float32 volts[3];          // 44-55: Voltages for phase A, B, and C
  float32 freq;              // 56-59: Line frequency (Hz)
  float32 power[3];          // 60-71: Real powers for phase A, B, and C
  float32 reacPower[3];      // 72-83: Reactive powers for phase A, B, and C
  uint16 crcB;               // 84-85: 16 bit CRC on entire log record
  // 86 bytes total
} TNomLogRecord;
 
// This structure / variable is a bitfield used to track events. It is logged and cleared with
// each log record, and bits are set when events happen.
typedef union {
  uint8 status;                 // Byte containing all status bits
  struct {                // Neuron C stores these most significant bit first
    uint8 powerFail:1;          // This is the first log record after power up
    uint8 clockChange:1;        // The clock was changed by >= 15 seconds
    uint8 calibrationChange:1;  // The calibration was changed
    uint8 configChange:1;       // The configuration was changed: nciCtAmps, nciDemPerMins, 
                                //  nciDemSubints, nciLogMinutes, nciCreepLimit.
    uint8 nodeOnline:1;         // First log record since coming online
    uint8 internalError:1;      // An internal error occurred
    uint8 nodeReset:1;          // The WattNode was reset (not due to power-up).
    uint8 res2:1;               // Reserved
  } bits;
} TLogStatus;