Keithley 2001 User Manual

Front Panel Operation
3-43
COUPLING
This parameter selects the input coupling for the frequency
function. When AC coupling is selected, a DC blocking ca-
pacitor is placed in series with the input. This removes the
DC component of the input signal.
When AC+DC coupling is selected, the blocking capacitor is
removed. Subsequent frequency measurements will reflect
both the AC and DC components of the signal.
You can set the frequency coupling as follows:
1. From the CONFIGURE FREQUENCY menu, select
COUPLING and press ENTER. The following menu is
displayed:
SET FREQ COUPLING
AC AC+DC
2. Highlight the desired coupling and press ENTER.
Multiple displays
There are two multiple displays just for the frequency func-
tion:
• Period calculation
• Trigger level
The multiple display showing the period of the waveform is
calculated from the frequency measurement and, as such, is
only available when the frequency does not equal 0Hz. It is
also unavailable when math is enabled.
The trigger level multiple display is the same message that is
displayed when the trigger level is changed, but it is a perma-
nent display.
3.4.5 Temperature
The Model 2001 measures temperature with two different
sensor types: RTDs and thermocouples. With RTDs, the
Model 2001 can measure temperature between -200°C and
+630°C. RTDs can be connected to the input terminals or the
optional Model 2001-SCAN scanner card.
With thermocouples connected to an external thermocouple
card, such as a Model 7057A or 7402 in a Model 7001
Switch System, the instrument measures temperature over a
range that is dependent on the thermocouple type. (Refer to
the specifications in Appendix A.)
Temperature measurements
Assuming “bench reset” conditions (see paragraph 3.12.1),
the basic procedure to measure temperature with a type
PT385 4-wire RTD (the default sensor) is as follows:
1. Connect the RTD sensor to the Model 2001 as shown in
Figure 3-17. You can use banana plugs (with the front or
rear inputs), or the optional Model 8680 RTD Probe
Adapter (with the front inputs). Place the INPUTS but-
ton in the appropriate position. RTDs can also be con-
nected to the optional Model 2001-SCAN scanner card.
(See the Model 2001-SCAN manual.)
2. Select the TEMP function.
CAUTION
Do not exceed 1100V peak between IN-
PUT HI and LO, or 350V peak between
SENSE Ω4 WIRE HI and LO, or instru-
ment damage may occur.
3. Observe the display. If the “Overflow” message is
shown, the RTD might not be connected properly.
4. Take a reading from the display.
The procedure for measuring temperature with 3-wire and 2-
wire RTDs is similar. (See Figures 3-18 and 3-19 for connec-
tion diagrams.) Be sure that the temperature function is con-
figured for the correct sensor type. (Use the 4-WIRE-RTD
selection for a 3-wire RTD sensor.)
To measure temperature with thermocouples, you need to
connect the thermocouples to a suitable external scanner
card, such as the Keithley Model 7057A or 7402. These
cards must be inserted into a Model 705 or 706 Scanner or
the Model 7001 Switch System, as shown in Figure 3-20.
The thermocouple cards use Channel 1 as the reference junc-
tion, and must be configured on the Model 2001 for voltage
reference and offset.

Keithley 2001 Specifications

General

Brand	Keithley
Model	2001
Category	Multimeter
Language	English