The Model 195A Digital Multimeter is a fully programmable
instrument with 5½ digit resolution. In standard
configuration, the Model 195A is capable of DC voltage
measurements between 100nV and 1000V on six ranges,
2-terminal and 4-terminal resistance measurements between
100µΩ and 20MΩ on seven ranges and temperature measurements
in the range of -220°C and +630°C and between -360°F and +
1100°F. The instrument is designed to work with platinum RTD
probes, a factor which contributes to high accuracy.
With the optional Model 1950 ACV and AC and DC current
option installed, the Model 195A can make TRMS AC voltage
measurements between 1/A/ and 700V on five ranges, TRMS AC
current measurements between 1nA and 2A on five ranges and
DC current measurements between 100pA and 2A on six ranges.
The versatility of the Model 195A DMM is further enhanced by
the inclusion of a standard IEEE-488 interface. A highlight
of Model 195A operation is its digital calibration feature
which allows the user to easily perform calibration from the
1.2 MODEL 195A FEATURES
Some important Model 195A features include:
1. Standard IEEE-488 Interface. A standard IEEE-488
interface allows the Model 195A to be programmed from a
system controller; readings may also be transmitted over the
bus to other instrumentation in the talk-only mode.
2. Front Panel Programs. Numerous internal programs to
control various operating modes such as digital calibration
and IEEE-488 parameters are easily entered from the front panel.
3. Non-Volatile (NV) RAM Storage. A non-volatile RAM stores
calibration constants, certain IEEE operating parameters,
and line frequency values even when the power is turned off.
4. Digital Calibration. The Model 195A may be easily
calibrated by applying an appropriate calibration signal and
running the front panel calibration program or by commanding
it over the bus. The calibration level may be at full range,
or at some value entered from the front panel or over the
5. Data Storage. A data storage buffer is included to allow
up to 100 readings to be internally stored at a
user-selected rate. The buffer may be read and controlled
from the front panel or over the IEEE-488 bus. In the
talk-only mode, the output rate can also be programmed.
6. Front and Rear Panel Input Terminals. Input terminals are
duplicated on the front and rear panels to allow easy
connections in both bench and rack-mounted situations. The
selected set of inputs is controlled by the rear panel sw'itch.
7. Trigger Input and Output. The Model 195A may be triggered
to take readings by applying an external trigger pulse or by
pushing a front panel button. A separate output pulse, which
is active w'hen the instrument completes a reading, is also
available on the rear panel.
8. Auto Ranging. The Model 195A includes a fast auto ranging
feature for easier measurements.
9. Front Panel Zero. A single front panel zero control
allows the user to store a separate zero offset for each
10. Filtering. Digital filtering is selectable from the
front panel or bus.