Keithley 2002, User Manual

Page: 50 / 366

Front Panel Operation
2-33
INPUT-TERMINALS
Both the volts and amps input terminals can be used to mea-
sure frequency. The upper limit on the voltage terminals is
15MHz; on the amps terminals it is 1MHz. The voltage limit
is subject to the 2
×
10
7
V•Hz product.
VOLTAGE: Specifies the voltage input terminals for fre-
quency measurements.
CURRENT: Specifies the AMPS input terminals for fre-
quency measurements.
COUPLING
This parameter selects the input coupling for the frequency
function.
AC:
With AC coupling selected, a DC blocking capacitor is
placed in series with the AC measurement circuit. This re-
moves the DC component from the input signal.
AC+DC:
When AC+DC coupling is selected, the blocking
capacitor is removed. Subsequent FREQ measurements re-
flect both the AC and DC components of the signal.
Multiple displays
There are two multiple displays just for the frequency
function:
Table 2-22
CONFIGURE FREQUENCY menu structure
Menu item Description
MAX-SIGNAL-LEVEL
1V, 10V, 100V, 1000V, TTL
1mA, 10mA, 100mA, 1A
Display maximum signal level menu:
Select maximum voltage level for voltage inputs.
Select maximum current level for current inputs.
RESOLUTION
4-DIGITS, 5-DIGITS
Display resolution menu:
Select a specific resolution.
INPUT-TERMINALS
VOLTAGE
CURRENT
Input terminals for frequency measurements menu:
Select INPUT HI and INPUT LO terminals.
Select AMPS and INPUT LO terminals.
COUPLING
AC
AC+DC
Coupling menu:
Select AC coupled measurements.
Select DC coupled measurements.
Notes:
1. The maximum signal level menu is coupled to the input terminals menu, i.e., voltage levels are shown if voltage is the selected
input.
2. With the Model 1801 Nanovolt Preamp installed and enabled, the maximum signal level is fixed at 2mV.
• 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.
2.4.5 Temperature
The Model 2002 measures temperature with two different
sensor types: RTDs and thermocouples. With RTDs, the
Model 2002 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.
When using thermocouples, the instrument measures tem-
perature over a range that is dependent on the thermocouple
type (refer to the specifications in Appendix A). Thermocou-
ples can be connected to the Model 2001-TCSCAN card
(which plugs into the option slot of the Model 2002), or to an
external thermocouple card, such as a Model 7057A or 7402
installed in a Model 7001 or 7002 Switch System.