ProSoft Technology PTQ-AFC - Manual (Page 128)

Quick Start PTQ-AFC ♦ Modicon Quantum Platform
User Manual Liquid and Gas Flow Computer for Hydrocarbon Products
Page 128 of 259 ProSoft Technology, Inc.
June 23, 2011
IF ( my_record < 0 OR my_record
 events_on_file ) THEN
[record is not on file]
EXIT this procedure
3 Calculate Modbus address.
Modbus_address := ( my_record * 8 ) + 40008
Procedure (D): Download all events not yet downloaded.
The downloading application should download the entire Log, starting at the
oldest event not yet downloaded and extending through all newer events.
1
Fetch event number of oldest event not yet downloaded.
downloadable_event := oldest_not_downloaded
2 Determine whether any more events remain to be downloaded.
IF ( downloadable_event == next_event ) THEN
[all events have been downloaded]
EXIT this procedure
3 Download this event.
a) Calculate record number.
my_event := downloadable_event
record_position := { via Procedure (B) }
b) Calculate Modbus address.
my_record := record_position
Modbus_address := { via Procedure (C) }
c) Download the event with Modbus.
Set Modbus Function Code := 4, Read Input Registers
Set Modbus Number of Registers := 8
Set Modbus Register Address := Modbus_address
Execute
Copy the returned data to permanent storage
4 Step to next event and loop.
downloadable_event := ( downloadable_event + 1 ) AND 0x0000FFFF
GOTO step 2.
When the download is complete, and the downloaded events have been logged
to disk, the AFC should be told of this fact by issuing the "download complete"
Site Signal. This signal updates the header to show that all records have been
downloaded, unlocking the Log for further events, and (if "Event log unlocked" is
clear) posts a "download" event. A download may be performed at any time; it is
not necessary to wait for the log-full condition in order to download.
An application that downloads the event log should explicitly include the event
number in any copy of the event that it stores in its own database.