Experimental Physics and
Industrial Control System

Hi folks!

 

I was working on the installation instructions to make them a bit more clear, and I ran across some caput behavior that I didn’t expect, but I’m not sure if that’s just because I’m not sure what to expect.  I looked at the CAref.html doc (https://epics.anl.gov/base/R3-15/7-docs/CAref.html#CommandTools) but this points to EPICS Base R3, and I didn’t know if there were any chances for R7.

 

Anyway, it looks to me like the MDEL field in my test.db only affects camonitor, and not caget. 

 

Test.db:

 

record(ai, "temperature:water")

{

    field(DESC, "Water temperature in the fish tank")

    field(MDEL, "0.01")

}

 

Caput commands:

 

$ caput temperature:water 15.6

Old : temperature:water              15.5003

New : temperature:water              15.6

$ caput temperature:water 15.6001

Old : temperature:water              15.6

New : temperature:water              15.6001

$ caput temperature:water 15.61

Old : temperature:water              15.6001

New : temperature:water              15.61

$ caput temperature:water 15.62

Old : temperature:water              15.61

New : temperature:water              15.62

 

And from camonitor:

 

temperature:water              2021-05-13 13:36:04.090862 15.6 

temperature:water              2021-05-13 13:36:14.587731 15.62 

It looks like the MDEL only suppresses events (interrupts?  Not sure of the terminology used here) from changes smaller than MDEL and doesn’t actually suppress updates to the IOC.  I don’t know enough to tell if this is the intended behavior or not, and I’m quite confident that I didn’t get all the terminology correct.

     Greg

 

--

Gregory Leblanc

Accelerator Engineer

Edwards Accelerator Lab - Ohio University

123 University Terrace

Athens, OH 45701

leblanc at ohio.edu

M: (401) 52-OUAL1 or (401) 526-8251