I think there’s a copy/paste error in that example, listing the same channel name twice.
As for scan vs. monitor:
Both internally “monitor” the channel and receive an update whenever the IOC sends an update, which for analogs depends on the SCAN and ADEL of the record.
<period>00:10:00</period><scan/> will write the most recently received value every 10 seconds.
<monitor/> will write every received, well, monitor, but because of internal buffering you should provide an estimated change period. So <period>1.0</period><monitor/> means: Please write every received value,
and assume that you won’t get them more frequently than once every second.
Longer explanation can be found in in the older manual.pdf on
https://controlssoftware.sns.ornl.gov/chanarch/, section 2.3 Sampling Options.
From:
Tech-talk <tech-talk-bounces at aps.anl.gov> on behalf of Geoffrey Savage via Tech-talk <tech-talk at aps.anl.gov>
Date: Wednesday, March 27, 2024 at 1:04 PM
To: tech-talk at aps.anl.gov <tech-talk at aps.anl.gov>
Subject: [EXTERNAL] archive engine scanned vs sampling