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TC815
DS21474B-page 12
2002 Microchip Technology Inc.
5.0
MANUAL RANGE SELECTION
The TC815 voltage and resistance auto-ranging fea-
ture can be disabled by momentarily bringing RANGE
(Pin 59) to digital ground potential (Pin 58). When the
change from auto-to-manual ranging occurs, the first
manual range selected is the last range in the Auto-
Ranging mode.
The TC815 power-up circuit selects auto-range opera-
tion initially. Once the manual range option is entered,
range changes are made by momentarily grounding
the RANGE control input. The TC815 remains in the
Manual Range mode until the measurement function
(voltage or resistance), or measurement option (AC/
DC,
/LO
) changes. This causes the TC815 to return
to auto-ranging operation.
The “Auto” LCD annunciator driver is active only in the
Auto-Range mode. Table 5-1 shows typical operation,
where the manual range selection option is used. Also
shown is the extended resolution display format.
Also see Figure 5-1 through Figure 5-3.
Note
1:
2:
3:
A flashing MSD is shown as a “1”. A flashing MSD indicates the TC815 is over-ranging if all other digits are zero.
The first manual range selected is the last range in the Auto-Ranging mode.
A flashing MSD with a non-zero display indicates the TC815 has entered the Extended Resolution Operating mode. An
additional 1000 counts of resolution is available. This extended operation is available only in manual operation for voltage,
resistance and current measurements.
= Momentary ground connection.
4:
TABLE 5-1:
MANUAL RANGE OPERATION
Input
DC Volts
AC Volts
Ohm
LO Ohm
23.5V
18.2V
18.2k
2.35M
Range
Display
Range
Range
Display
Range
Range
Display
Power-on
Auto-Range
Operation
200mV
2V
20V
200V
“1”00.0V
1.000V
“1”0.00V
23.5V
2V
20V
—
—
“1”000V
18.20V
—
—
200
2k
20k
—
“1”00.0
“1”.000k
18.20
—
2k
10k
200k
2000k
“1”.000k
“1”.0.00k
“1”.00.0k
“1”350k
Manual Operation
Input
DC Volts
AC Volts
Ohm
LO Ohm
23.5V
18.2V
18.2k
2.35M
# of Range
Changes
(See Note 4
)
Range
Display
Range
Range
Display
Range
Range
Display
1
2
3
4
5
6
7
8
200V
200mV
2V
20V
200V
1000V
200mV
2V
23.5V
“1”00.0V
1.000V
“1”3.50V
23.5V
24V
“1”00.0mV
“1”.000V
20V
2V
20V
20V
600V
2V
20V
200V
18.20V
“1”.000V
18.20V
18.2V
19V
“1”.000V
18.20V
18.2V
20k
200
2k
20k
200k
2000k
200k
2k
18.20V
“1”00.0
k
“1”000k
18.20k
18.2k
19k
“1”00.0
“1”.000k
2000k
2k
20k
200k
2000k
2k
20k
200k
“1”350k
“1”.000k
“1”0.00k
“1”00.0k
“1”350k
“1”.000k
“1”0.00k
“1”00.0k