Historical Data Enquiry

This chapter describes data retrievability feature to send downlink command to enquire the historical data stored in the device. Before that, ensure the device time is correct and data storage feature is enabled to store data.

Command Format:
Item Channel Type Byte Description
Enquire Data in Time Point fd 6b 4 Unix timestamp, Unit: s
Enquire Data in Time Range fd 6c 8 Byte 1-4: Start timestamp, Unit: s

Byte 5-8: End timestamp, Unit: s
Stop Query Data Report fd 6d 1 ff
Data Retrievability Interval f9 0e 2 UINT16, Unit: s, Range: 30~1200, Default: 60
Reply Format:
Item Channel Type Byte Description
Enquiry Result fc 6b/6c 1 00: Enquiry success. The device will report the historical data according to data retrievability interval.

01: Time point or time range invalid

02: No data in this time or time range
Note:
  1. Use Unix Timestamp Converter to calculate the time.
  2. The device only uploads no more than 300 data records per range enquiry.

  3. When enquiring the data in time point, it will upload the data which is closest to the search point within the reporting interval range. For example, if the device’s reporting interval is 10 minutes and users send command to search for 17:00’s data, if the device find there is data stored in 17:00, it will upload this data; if not, it will search for data between 16:50 to 17:10 and upload the data which is closest to 17:00.

Example:
Enquire the historical data in a time range.
fd6c 64735b63 7c885b63
Channel Type Value
fd 6c Start time: 64 73 5b 63 => 63 5b 73 64 = 1666937700s

End time: 7c 88 5b 63 => 63 5b 88 7c = 1666943100s
Reply:
fc6c00
Channel Type Value
fc 6c 00: Enquiry success

21ce 0d755b63 01 8085 1400000000000000 ddff000000000000

Channel Type

Time Stamp

Value
21 ce 0d 75 5b 63 => 63 5b 75 0d=1666938125s

01: Channel 2

Crtl: 8085 => 1 000010 110000000

Bit15: 1=>signed

Bit14-9: 000010 => 02=Input16_AB

Bit8: 1=> Fetch success

Bit7-6:10 = Two registers

Bit5-4:00 => Normal Data

Value 1: 14 00 00 00 00 00 00 00=>00 00 00 00 00 00 00 14=>20

Value 2: dd ff 00 00 00 00 00 00=>00 00 00 00 00 00 ff dd => -35