Service manual

METTLER TOLEDO
DIVA Service Manual 55
6.1.8.4 Description of the Dialog
A dialogue will always be initiated by the POS-system.
Description of weighing operation
The POS-system transmits one of the Records 01, 03, 04 or 05.
The scale answers (if no errors) with ACK and displays the transmitted data. The POS-system
now can request the weighing result from the scale by transmitting EOT ENQ. If the result is
known the scale answers with Record 02.
If there is an error, the scale answers with NAK. The cause of the error can be explained by the
POS-system sending Record 08 and receiving Record 09. If the status is 20 or 22, the weighing
results can be requested again by retransmitting EOT ENQ. In the case of other errors, the
operation has to be started at the beginning (records 01, 03, 04 or 05).
Description of weighing operation with request of checksums
At certain times, the scale will request from the POS-system the calculation and transmitting of
checksums. This will happen in the course of a weighing operation after receiving of one of the
records 01, 03, 04 or 05, and happens if one of the following events occurs:
 the scale was just powered on
 there was an error detected before
 50 weighing operations have taken place
 the version number was displayed by the scale (record 20)
Order of events:
 The POS-system transmits one of the Records 01, 03, 04 or 05.
 The scale answers with Record 11.
 Example: STX 11 ESC 247 ETX (transmit record 10, use random number 47H)
 The POS-system now calculates the checksums, encodes and transmits them by record 10 to
the scale.
 The scale responds Record 10 first with ACK.
 The POS-system continues as with a normal weighing operation by transmitting EOT ENQ.
 Only now the scale responds the validity of the checksums by Record 11.
 If the checksums were valid, the scale transmits STX 11 ESC 1 ETX otherwise STX 11 ESC 0
ETX.
 Regardless whether the response was positive or negative, the POS-system has to repeat the
original weighing operation.
Status information
The POS-system is able to get status information from the scale by record 08.
Version number on/off
The POS-system can display the version number of the software in the scale. If the scale
receives record 20 EOT STX 20 ESC 1 ETX, it will display the version number until it receives EOT
STX 20 0 ETX. All other records will be ignored in between!
Please note that all dialogues must be initiated by the POS-system with EOT, and also every
response of the scale has to be answered by the POS-system with EOT !