SC Series Instruction Manual - Model SC500 page 45
Limi
ts
9
Chapter 9
Limits
9.1 Understanding Limits, Set Points and Return Points
Limits are only available if the instrument was purchased with Option 58a or 58h.
Limits are signal levels at which some action (such as a light to come on or go out,
or a switch to close) is desired to take place. The point at which this action takes
place is the
SET POINT
. The
RETURN POINT
is the point at which the action that
took place at the
SET POINT
returns to its original state.
If the
SET POINT
and
RETURN POINT
are identical and the signal level is
changing slowly near these points, “chatter” may result and the limit rapidly ener-
gizes and de-energizes. To keep this from happening, we can specify the
SET
POINT
at which the action would occur as well as the
RETURN POINT
where we
want the action to cease. If the amount of “dead band” between these two values
is more than the expected noise, the desired action will take place only once. The
SET POINT
and the
RETURN POINT
should always be separated to insure that
small amounts of noise on the signal will not become a problem.
A good general rule for
SET POINT
and
RETURN POINT
values is that they
should be separated by at least one percent of the full-scale value.
9.2 Wiring
Unless overridden by a application-specific SensoCode program, the Limits drive
the Relay pins of the Options connector. See “Options Connector” on page 31 for
details.
Summary of Contents for SC500
Page 8: ...page 8 008 0671 00 ...
Page 14: ...page 14 008 0671 00 ...
Page 18: ...page 18 008 0671 00 ...
Page 24: ...page 24 008 0671 00 ...
Page 38: ...page 38 008 0671 00 ...
Page 42: ...page 42 008 0671 00 ...
Page 50: ...page 50 008 0671 00 ...
Page 72: ...page 72 008 0671 00 ...
Page 82: ...page 82 008 0671 00 ...
Page 90: ...page 90 008 0671 00 ...
Page 116: ...page 116 008 0671 00 ...
Page 126: ...page 126 008 0671 00 ...
