Operation
3-7
An appropriate error message will be displayed if you
select one of the above multiple displays with the preamp
enabled. Also note that the FREQ bar graph range is lim-
ited to 2kHz with the preamp enabled. See paragraph
3.2.2 of the Model 2001 Operator’s Manual for more
information on using the multiple displays.
3.2.7 IEEE-488 bus operation
Table 3-7 summarizes additional IEEE-488 bus com-
mands necessary for preamplifier configuration. In gen-
eral, most of the IEEE-488 bus commands covered in
Section 4 of the Model 2001 Operator’s Manual can be
used with the Model 1801. However, the same operational
restrictions discussed in paragraph 3.2.5 apply to bus pro-
gramming. If you send an invalid program message, an
error will result.
NOTE
Additional commands that control dif-
ferential thermocouple temperature
operation are explained in paragraph
3.3.5.
Table 3-7
Preamplifier configuration commands
Command
Description
:INPut
:PREamp
:STATe <b>
:STATe?
:FILTer <name>
:FILTer?
Enables (ON or 1) or dis-
ables (OFF or 0) preampli-
fier.
Returns preamp state (1=ON
or 0=OFF)
Selects preamp filter
response (Name = SLOW |
MEDium | FAST)
Returns preamplifier state
(SLOW, MED, or FAST)
Notes:
1. Angle brackets (<>) are used to indicate parameter type. Do not
include brackets in programming message.
2. Upper-case letters indicate command short form.
Example 1: Enable Preamplifier
:INP:PRE:STAT ON
or,
:INPUT:PREAMP:STATE 1
Example 2: Select Filter Response
:INP:PRE:FILT MED
or,
:INPUT:PREAMP:FILTER MEDIUM
3.3
Measurements
3.3.1 DC voltage measurements
The Model 1801 can detect DC voltages as low as 1pV
and measure up to 2mV. Assuming “bench reset” condi-
tions (see paragraph 3.12.1 of the Model 2001 Operator’s
Manual), the basic procedure for making DC voltage
measurements is as follows:
1. Connect the input cable to the INPUTS terminals on
the preamplifier module, and connect the output leads
to the Model 2001 rear panel INPUT jacks (see Fig-
ure 3-2).
2. Set the INPUTS switch to the REAR position.
3. Press CONFIG DCV, then configure the speed, filter,
and resolution as required.
4. Press the DCV key to select the DC volts function.
5. Using the RANGE keys, choose a range consistent
with the expected voltage. (Available ranges are:
20µV, 200µV, and 2mV.)
6. Connect the input leads to the voltage source, as
shown in Figure 3-2.
CAUTION
Do not exceed 1V peak at 100mA
between the INPUTS HI and LO
terminals, or the preamplifier may be
damaged. (Inputs over 2mV peak will
require a one-minute recovery period.)