Lufft CHM 15k Nimbus, Manual

Page: 36 / 101

Communication RS485 & Ethernet
36 Revision R09, November 2016
8.2 Instrument Configuration using RS 485 interface
The user can change settings via the RS485 interface for:
l
control of the measuring process
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configuration of the communication interfaces
8.2.1 Reading a parameter
To read a parameter, you must trigger a command:
get<SPACE><RS485No>:<ParameterName><CR><LF>
If <ParameterName> is found to contain a valid designation according to table 4
or table 5, its value will be output as part of
<STX>get<SPACE><RS485No>:<ParameterName>=<Value>;<ASCII-
Two’s complement><CR><LF><EOT>
Example:
If the instrument serial number (Devicename) was preset to CHM060003, you
may query the name, using the short command
get 16:DVN<CR><LF>
The response to this query looks like this:
<STX>get 16:DeviceName=CHM15kd01;2B<CR><LF><EOT>.
Where each of the non-printable characters <STX>, <CR>, <LF> and <EOT>
stand for one byte with hexadecimal codes 02, 0D, 0A and 04 in this same
order. The value 2B represents the checksum of the two's complement formed
over the whole response line, excluding the two characters (2B) themselves, in
accordance with the established protocol response format (refer to
chapter 8.3.3 to 8.3.5).
8.2.2 Setting a parameter
A command line like
set<SPACE><RS485No>:<ParameterName>=<Value><CR><LF>
can change a desired configuration parameter. The successful completion of a
change in parameter setting is reported via:
<STX>set<SPACE><RS485No>:<ParameterName>=<Value>;<ASCII-
Two’s complement><CR><LF><EOT>
If <Value> is found to be within permissible limits, the newly set value
<NewValue> meets this requirement. If an entry is found to be above the upper
limit or below the lower limit, the permitted maximum or minimum value will be
applied instead. With alphanumerical entries the default value will be applied as
<Value>.
Example:
Following a command,
set 16:Unit(m/ft)=ft<CR><LF>
or in short form