User manual

Table Of Contents
NOTE
The MMP sends tones twice spaced 40 seconds apart, as a backup. The UIM should
automatically generate a 4800 Hz tone for 2.5 seconds detectable by the Tone Detect board on
the SIM. In some instances the UIM tone is not sent (this occurs because the the SBE44 was
not specifically designed for the MMP inductive modem interface). The MMP initiates the
wake-up tone to ensure that the SIM detect line is properly set.
2. The surface controller (SC) monitors the ‘Tone detect’ board tone detect line. Receipt of
a tone indicates that the MMP is ready to transmit data. The SC powers on the SIM and
sends the necessary commands to upload the data.
3. The MMP listens for 3 intervals of 40 seconds each for one of the recognized data upload
commands.
4. When power is applied to the SIM board, the board sends a wake-up signal down the
mooring wire (if the UIM is up and running the wake-up signal is ignored). If the UIM
is not ready, this wake-up activates the UIM.
5. A transmit-receive-acknowledge sequence proceeds as follows until the MMP has sent
the entire file:
If the SC requires the newest data it relays a #nnREQNEW command to the MMP
(eg. #01REQNEW). The ‘#’ defines the request to the UIM to transmit ascii data
with a termination character, configured as ‘>’; nn is the ID of the UIM attached to
the MMP; REQNEW is the command relayed by the UIM to the MMP.
Everything after the nn ID is relayed verbatim to the UIM, including the filename
in the case of REQFIL.
The MMP responds by sending the next file available from the files collected since
the last successful transmission. If the operator has chosen to keep a limited
number of files and there is trouble transmitting, the oldest files may be deleted
before they are transmitted. This risks the loss of the oldest data, but does not
interfere with the algorithm which sends the next available data. The data is sent in
packets (defined in the ‘Data Format’ section of this appendix) and the transaction
process requires the surface to acknowledge receipt of each packet.
Appendix J-4