aci eRCM Express, Руководство пользователя

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mCore Firmware Ver 01.10 Ver 2019-Oct-29 Page 86 of 97
If a reciprocating compressor has a lot of clearance pockets, then at medium to higher
compression ratios, it is not uncommon for many of the lower-load load steps to be clipped
due to Low Volumetric Efficiency issues.
Thus, trying to bring the unit online, or even performing a normal stop, can be troublesome
as the power change on the engine or motor between safe load steps may be too large.
eRCM Express will not select safe Next Steps Up/Down if they result in too large of a load
change on the driver.
However, certain load steps, such as those determined to have Low Volumetric Efficiency
(LowVE) issues and/or Predicted High Discharge Temperature (HiTd) issues, can be used
as transitional load steps. That is, it is generally ok to transverse through these types of load
steps, but the unit cannot run (cumulatively) in them for more than a few minutes.
•
Some units have experienced serious cylinder damage due to running in LowVE
after only about ten (10) minutes. Other units run in LowVE areas for hours and days
without issues (other than cylinder getting hot, but not too hot). Thus, the amount of
safe time needs to be determined by the end-user.
o
Generally, running in LowVE less than 2-3 minutes is not an issue.
Thus, for some end users, they may need to set the
IgnoreNonCriticalErrors register
(ACI_Inputs[57]; Reg#40115)
to a 1 during Normal Start Up and Normal Stopping. This
allows the unit to load smoother, albeit it may select certain load steps that put the unit in
LowVE or HighTd. However, if the total time for these events is short (0-3 minutes), then
no real concerns are raised.
•
After the end-user’s specified time limit, if loading/unloading goals are not achieved,
then
IgnoreNonCriticalErrors register must be set back to 0. If no safe load steps
are then determined, then Shut Down is the prudent action to take.
Alternative use of
IgnoreNonCriticalErrors :
•
If during normal operations, OptimalLS
≠
-1 and OptimalLS
≠
CurrLS, but
NextStepUp = -1, then this means that there is an opportunity to load the unit up
more, but the potential load change from CurrLS to OptimalLS is too large to take.
o
By electing to ignore some non-critical safety issues for a few minutes, the
unit may be able to step though some transitional load steps to reach
OptimalLS.