
Appendix A _________________________________________________________ Modbus Reference
VAISALA _______________________________________________________________________ 177
NOTE
Resetting, powering up the transmitter, or reselecting the
Modbus mode
(by serial command or with the user interface) resets all
Modbus
diagnostic counters and cancels any “Listen Only” mode.
Device Identification Objects
MMT330 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.
Table 42 MMT330 Modbus Device Identification
Product code (e.g. “MMT330”)
Software version (e.g. “5.10”)
“http://www.vaisala.com/”
Product name of the instrument
Serial number (e.g. “D0710040”)
Date of the last calibration
(e.g. “2011-02-07”, empty if not
Information text of the last calibration
(empty if not available)
Exception Responses
Exception responses from the transmitter are according to the Modbus
Application Protocol Specification V1.1b.
Table 43 MMT330 Modbus Exception Responses
Unsupported function code
Address out of valid ranges
Otherwise invalid request
Accessing unavailable (unsupported or temporarily missing) registers
inside ranges specified in Table 36 does not generate an exception.
“Unavailable” value (a quiet NaN for floating point data or zero for
integer data) is returned instead. An exception is generated only for any
access outside the register blocks defined in section Register Map on
page 172.
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