Vaisala HMM105 - Manual (Page 16)

Technical Reference _________________________________________________________________
14 ________________________________________________________________ M211638EN-A
Set_Parameter
The Set_Parameter command (ID 82h) writes parameter values to non-
volatile memory. You can use it to set the operational parameters of the
HMM105. Depending on the change, the functionality of the HMM105
may not change immediately.
The length of the invoke message varies depending on the data length.
The master must write as many bytes as indicated in the frame length of
the invoke message. If the master tries to write a longer or shorter
message, HMM105 rejects the message.
Table 17 Set_Parameter Invoke Message
Message Segment Length Content
I 2 C address 1 byte I 2 C address (write)
Command ID 1 byte Always 82h
Device address 1 byte See Table 5 on page 4
Frame length 1 byte Varies according to data length,
07h ... 38h.
Data 1 byte Parameter ID
1 ... 50 bytes Parameter value
Checksum 2 bytes See section Checksum on page 9
Table 18 Set_Parameter Response Message
Message Segment Length Content
I 2 C address 1 byte I 2 C address (read)
Status 1 byte See section Status Byte on page 9.
Command ID 1 byte Always 82h
Device address 1 byte See Table 5 on page 4
Frame length 1 byte Always 08h.
Data 1 byte Parameter ID
1 byte Return code. See Table 19 below.
Checksum 2 bytes See section Checksum on page 9
Table 19 Set_Parameter Return Codes
Code Meaning
0 Ok
1 Unknown parameter ID
2 Not writeable parameter
3 Value field too long
4 Value field too short
5 Data value not accepted