Keithley 2002, User Manual

Page: 56 / 366

Front Panel Operation
2-39
There is a multiple display for the temperature function that
shows the reading expressed in all three temperature units.
SPEED
The SPEED parameter sets the integration time of the A/D
converter, the period of time the input signal is measured (al-
so known as aperture). It is discussed in paragraph 2.4.1, DC
and AC voltage. Only the differences for temperature are
noted here.
SET-BY-RSLN:
This parameter optimizes the integration
time for the present resolution setting. The defaults for set-
by-resolution integration times of temperature are listed in
Table 2-24.
FILTER
FILTER lets you set the digital filter response. The filter
menu is available from the function configuration menus (i.e.
CONFIG TEMPERATURE) or by pressing CONFIGURE
FILTER with the desired function already selected. All of the
parameters (menu items) for FILTER are explained in para-
graph 2.9. Since the AUTO parameter has specific effects on
TEMP, it is covered here.
The advanced filter is not available for the temperature func-
tion.
AUTO:
This parameter for a digital filter optimizes its use
for the present measurement function. The defaults for auto-
matic filtering of temperature are as follows:
Averaging
State Type Readings Mode
On Averaging 10 Moving
Table 2-24
Temperature integration time set-by-resolution
Resolution
degrees Resolution
digits Integration
time
1 degree
0.1 degree
0.01 degree
0.001 degree 3.5d
4.5d
5.5d
6.5d 1.0 PLC
1.0 PLC
1.0 PLC
1.0 PLC
Note: If the integration time is SET-BY-RSLN and the resolution
AUTO, the integration time will be 1.0 PLC and the resolution
set by sensor.
RESLN
Resolution for temperature is not expressed in number of
digits, but in fractions of a degree, ranging from 1° to 0.001°.
AUTO:
Display resolution is dictated by temperature sensor
type. Table 2-25 lists the resolution for the various sensor
types.
1°, 0.1°, 0.01°, or 0.001°:
Sets display resolution for TEMP.
Multiple displays
The available multiple displays for temperature depend on
the presently selected sensor type, except for the multiple
display that shows temperature in three different units:
+0000.0 °C
+0000.0 °F
+0000.0 K
RTD measurements have a multiple display for the resis-
tance of the RTD, such as:
RTD Resistance = +0.0000
Ω
Thermocouple measurements have multiple displays for the
thermocouple voltage and reference junction temperature.
Sample displays are:
Thermocouple Voltage = 0.0000mV
Reference junction = 00.0 °C
Note that the reference junction temperature is shown in the
units selected by the SET TEMP UNITS menu. The display
of two blinking question marks at the right of the reference
junction temperature indicates an overflow of the reference
junction measurement. Thermocouple measurements will be
made normally using the existing reference temperature
value.
Table 2-25
Temperature auto resolution
Sensor
Resolution
Degree Digits
RTDs 2-, 3-, or 4-wire
Thermocouples J, K, T, E
Thermocouples R, S, B, N 0.01
0.1
1 5.5d
4.5d
3.5d
Note: If the resolution is AUTO and the integration time SET-BY-
RSLN, the integration time will be 1.0 PLC.