Burkert Type 8056 - Manual (Page 68)

- 68 - RS232_485_ETP_MODBUS_BU_REV02.doc
• Save the modified file and close the Notepad application.
• Send the following command to the instrument: “ACODE=xxxxx,L2ACD=0”, where the xxxxx stays
for the actual L2 code set in the instrument. This disables the Level 2 code, otherwise it should be
necessary to repeat the command “ACODE=xxxxx” at each line.
• Select “Transfer” on the menu bar of the Hyper terminal, and choose “Send Text”: a dialog box
window will appear
• Set the filename that you have modified before as the file to be send in the dialog box and press
“enter”
• The display will show a series of lines scrolling, with all the configuration parameters contained in
the file.
• Wait until the last command is sent.
• Eventually set again the Level 2 code with the command “L2ACD=xxxxx”. Do not forget the code
entered now!
NOTE: some commands sent with this method probably will fail with a “1:CMD ERR”, “2:PARAM
ERR” or “5:ACCESS ERR” message. This is normal because some parameters can be read at
certain access level but they can’t be written at the same level, or some others can be read but they
can’t be written in the actual configuration context.
4.3. HTP PROTOCOL
The HTP protocol (with only one “T”, to be not confused with the HTTP protocol, which is a completely
different thing) is a very simple way to exchange data between the flow meter and an application like the
Windows-based Hyper-Terminal. With the HTP protocol it is possible to read and to write the parameters of
the flow meter and to perform some internal functions. The data are exchanged using ASCII strings
terminated by the carriage-return character. The maximum size of the input or the output strings is about
1000 characters when a terminal is attached directly to the serial port, or 160 characters if the
communications is performed using SMS. When the maximum size is exceeded in the input, the entire
string entered is discarded and an error message is issued. When the maximum size is exceeded in the
output, the execution of the commands is still performed but the output information are lost and an error
message is issued. The output string length depends exclusively on the type of commands given in the
input, some commands produces a very short answer and some other gives a very long string. Care must
be taken to not saturate the output capacity, otherwise the expected information will be lost.
IMPORTANT: Before accessing or modifying some parameters, a privilege level must be acquired. This
can be done sending an access code that matches the L2 code of flow meter as first command in the input
string (ACODE=n). The code lifetime is limited to the execution of the string that contain it, when the input
string is evaluated completely, it expires. Thus it is necessary to provide the access code each time a
parameter must be changed or inspected. If the L2 code of the instrument is set to zero, the access code is
no more necessary.
Special characters. The following characters have special meaning in the protocol and thus they can’t be
used for other purposes:
• <CR> carriage-return character, value 13 decimal, 0D hexadecimal, terminates the input string and
starts the elaboration
• <LF> line-feed character, value 10 decimal, 0A hexadecimal, may follows the <CR> but it is never
considered
• ? question mark character, value 63 decimal, 3F hexadecimal, it is an operator character
• = equal sign character, value 61 decimal, 3D hexadecimal, it is another operator character
• : colon character, value 58 decimal, 3A hexadecimal, it is the comment-separator character
• , comma character, value 44 decimal, 2C hexadecimal, it is the command-separator character