Sensor Electronics SEC 3000, Instruction And Operation Manual

Page: 331 / 489

Reasonable broadcast times should be held to no longer than 2 seconds, that way
only one sensor gas detection interval is missed per scan loop (essentially, every other
sample, since the SEC 3000 sensor outputs a gas value every 1.65 seconds), worse case.
This is accomplished primarily by adjusting the number of records broadcast per gas
detection scan loop.
Example Scan Loop (100 gas detectors) with a Sliding Window (25 Records):
Sensor Electronics Corporation Page 7 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
Gas Detector Loop 1:
ID 1 – 100 scanned again
7 seconds
StatCast Output:
ID 1 – 100 Records output
4 seconds
Elapsed Time:
7+4 = 11 secs
7+4 = 11 secs
Gas Detector Loop 2:
ID 1 - 100 scanned again
7 seconds
StatCast Output:
ID 1 – 100 Records output
4 seconds
Example Scan Loop (100 gas Detectors) without a Sliding Window (100 records):
7 seconds
Elapsed Time:
Gas Detector Loop 1:
7+1 = 8 secs
8+7+1 = 16 secs
16+7+1 = 24 secs
24+7+1 = 32 secs
ID 1 – 100 scanned again 1 second
Sliding Window (1 of 4):
ID 1 – 25 Records output 7 seconds
Gas Detector Loop 2:
ID 1 - 100 scanned again 1 second
Sliding Window (2 of 4):
ID 26 – 50 Records output 7 seconds
Gas Detector Loop 3:
ID 1 - 100 scanned again 1 second
Sliding Window (3 of 4):
ID 51 – 75 Records output 7 seconds
Gas Detector Loop 4:
ID 1 - 100 scanned again
1 second
Sliding Window (4 of 4):
ID 76 – 100 Records output