Appendix B _________________________________________________________ Modbus Reference
VAISALA _______________________________________________________________________ 107
Device Identification Objects
HMW90 Modbus conforms to the extended identification level defined in
the Modbus Application Protocol Specification V1.1b. Both stream
access and individual access to the objects is supported.
Basic device identification consists of objects 0x00…0x02. Those values
should be used if the device must be identified to establish its Modbus
capabilities.
Table 45
HMW90 Modbus Device Identification
Object Id
Object Name
Description
0x00
VendorName
“Vaisala”
0x01
ProductCode
HMW95
0x02
MajorMinorVersion
Software version
(for example, “1.0.0”)
0x03
VendorUrl
“http://www.vaisala.com/”
0x04
ProductName
HMW90
0x80
SerialNumber
Serial number (e.g.
“H0710040”)
0x81
CalibrationDate
Date of the last calibration
(for example, “2012-08-07”,
empty if not available)
0x82
CalibrationText
Information text of the last
calibration (empty if not
available)
Exception Responses
Table 46
HMW90 Modbus Exception Responses
Code
Name
Reason
01
ILLEGAL FUNCTION
Unsupported function code
02
ILLEGAL DATA ADDRESS
Address out of valid ranges
03
ILLEGAL DATA VALUE
Otherwise invalid request
Accessing unavailable (unsupported or temporarily missing)
measurement data does not generate an exception. “Unavailable” value (a
quiet NaN for floating point data or 0x0000 for integer data) is returned
instead. An exception is generated only for any access outside the
register blocks defined in Table 40 on page 104.
