Keithley 2182, Руководство пользователя, Страница: 143 / 339

Limit operations
Limit operations set and control the values that determine the HI/IN/LO status of subsequent
measurements. The limit test is performed on the result of an enabled Rel, mX+b, or Percent
operation.
There are two sets of limits. Limit 1 uses high and low limits (HI1 and LO1) as does Limit 2
(HI2 and LO2). However, the HI/IN/LO status message only applies to Limit 1. Figure 8-1
illustrates the following limits which are the factory defaults:
Limit 1: HI1 = +1V and LO1 = -1V
Limit 2: HI2 = +2V and LO2 = -2V
Figure 8-1
Default limits
For the limits shown in Figure 8-1 , a reading of 1.5V is outside Limit 1 (which is the primary
limit). Therefore, the message “HI” will be displayed.
A beeper is also available for limit testing. There are three beeper options: NEVER,
OUTSIDE and INSIDE. These options are explained as follows:
NEVER — With this option, the beeper is disabled. Only the HI/IN/LO status message is
used for the Limit 1 test.
OUTSIDE — With this option, the beeper sounds when the reading is outside (HI or LO) of
Limit 1. Again referring to Figure 8-1 , a 1.5V reading is outside (HI) Limit 1. Therefore the
beeper will sound.
INSIDE — With this option, the beeper sounds when the reading is inside Limit 1 and/or
Limit 2. If the reading is inside Limit 1, the beeper will sound at its normal pitch. If the reading
is outside Limit 1 but inside Limit 2, the beeper will sound at a lower pitch. The beeper will not
sound for readings outside Limit 2. For the limits shown in
Figure 8-1 , a 0.5V reading will sound
the beeper at its normal pitch, a 1.5V reading will sound the beeper at a lower pitch, and for a
2.5V reading, the beeper will not sound.
NOTE To use the Limit 2 test, the INSIDE beeper mode must be selected. With NEVER or
OUTSIDE selected, Limit 2 is (in effect) disabled.
-2V
LO2
-1V
LO1
+1V
HI1
+2V
HI2
LO IN HI
Limit 1
Limit 2
0
Limits 8-3