Sensor Electronics SEC 3000, Инструкция по эксплуатации

Страница: 332 / 489

Sensor Electronics Corporation Page 8 of 15 SEC 3500 OI- StatCast
5500 Lincoln Drive RS232 Gas Status Text Broadcast
Minneapolis, Minnesota 55436 Configuration Manual
August 2
nd
, 2006 952-938-9486 Revision 1.1
Of course there is another way to avoid either the excessive data latency (24
seconds) shown in the sliding window example previously, or the missed gas detection
period (4 seconds) in the full burst shown in the immediate previous example; and that is
to increase the baud rate, and add line repeaters as needed. This can be accomplished
using the configuration utility to change rates, adjust record count and try and measure
before committing a final configuration. In the above example, a baud rate of 19,200
would decrease the time in the full burst example from 4 seconds to 2 seconds, and a
baud rate of 38,400 with multiple line repeaters (if the distance is long) would reduce that
to an acceptable delay of only 1 second.
Of course a compromise could be made, by increasing the baud rate from 9600 to
19200 (1 second per window burst of 50 records), and setting a sliding window of 50
records, producing a latency of only 2 scans or 7 seconds for the entire set. In this manner,
the gas detection loop is hardly impacted (1 seconds, quite acceptable), and the added
latency to acquire a full StatCast set is only 7 seconds.
The formatted output of StatCast is discussed in the next section, and
configuration of StatCast in the section following that.