Siemens Climatix S300 HRV - Page 160

Encoding of text string with multiple Registers
● BA-Properties representing text information are encoded as UTF8 text string.
● Pair wise mapping of two bytes of the text string to one MODBUS Register.
● The first byte of the text string is mapped to the MSB of the 1st MODBUS
Register (with the lowest Register address).
● On MODBUS the string is NUL terminated. Unused Registers or the LSB of the
last used Register shall contain the value NUL.
Example: BA-property, max. string length 20 byte, containing the string “hello
world” would be mapped to 10 MODBUS Registers as follows:
Register address Register data
x h e
x+1 l l
x+2 o
x+3 w o
x+4 r l
x+5 d NUL
x+6 NUL NUL
x+7 NUL NUL
x+8 NUL NUL
x+9 NUL NUL
Encoding of Date, Time information with multiple Registers
Register address Date
x Year (100…199) Month (1…12)
x+1 DayOfMonth (1…31) DayOfWeek (1…7)
Time
x+2 Hours (00…23) Minutes (00…59)
x+3 Seconds (00…59) HundredthsOfASecond (00…99)
Date:
● Date encoding uses 2 MODBUS Registers.
Date.Year:
● Represents year minus 1900.
● Note: Date information can only be from 2000.1.1 to 2099.12.31.
● 1:1 mapping of BA-Date.Year (1 octet) to Register bit15…bit8.
Date.Month:
● Represents month 1...12.
● 1:1 mapping of BA-Date.Month (1 octet) to Register bit7…bit0.
Date.DayOfMonth:
● Represents day of month 1…31.
● 1:1 mapping of BA-Date.DayOfMonth (1 octet) to Register bit15…bit8.
Date.DayOfWeek:
● Represents day of week 1...7 and
● 1:1 mapping of BA-Date.DayOfWeek (1 octet) to Register bit7…bit0.
Time:
● Time encoding uses 2 MODBUS Registers.
Time.Hours:
● Represents hours 0…23.
● 1:1 mapping of BA-Time.Hours (1 octet) to Register bit15…bit8.
Time.Minutes:
● Represents minutes 0...59.
● 1:1 mapping of BA-Time.Minutes (1 octet) to Register bit7…bit0.
Time.Seconds:
● Represents seconds 0...59.
● 1:1 mapping of BA-Time.Seconds (1 octet) to Register bit15…bit8.
Time.HundredthsOfASeco
nd:
● Represents hundredths of a second 0...99.
● 1:1 mapping of BA-Time.HundredthsOfASecond (1 octet) to Register bit7…
bit0.
Engineering of communicative devices
Modbus slave
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