Scanning Fundamentals - Keithley 2750 User Manual

7-2 Scanning

Scanning fundamentals

The Model 2750 can scan the channels of up to five installed Keithley switching modules.
Each scan channel can have its own unique setup. Aspects of operation that can be
uniquely set for each channel include function, range, rate, AC bandwidth, rel, filter, dig-
its, math, Ω offset compensation, TEMP transducers, limits, channel average, channel
ratio, and volts dB.
NOTE
There are SCPI commands to query the capabilities of the installed switching modules.
For example, the following queries are provided to determine which channels are available
for volts/2-wire ohms, and which channels are available for amps. Note that the returned
values for the Model 7700 switching module are shown in parenthesis.
SYSTem:CARD:VCHannel[:STARt]? <NRf> ' Query first volt/Ω2 channel (7700; "1").
SYSTem:CARD:VCHannel:END? <NRf>
SYSTem:CARD:ACHannel[:STARt]? <NRf> ' Query first amps channel (7700; "21").
SYSTem:CARD:ACHannel:END? <NRf>
where:
All the commands to query switching module capabilities are covered in
NOTE
Readings for scanned channels are automatically stored in the buffer. With
buffer auto clear enabled (which is the default), the buffer clears when the scan
is started. When disabled, scan readings are appended to the buffer. The
TRACe:CLEar:AUTO <b> command is used to enable/disable buffer auto clear
(Section 6).
A pseudocard can be installed in an empty slot. With the 7700 pseudocard
installed, the instrument will operate as if a Model 7700 switching module is
installed in the slot. This allows the user to configure a scan and exercise its
operation before the switching module is installed in the Model 2750. Use the
following commands to install 7700 pseudocards in empty slots:
SYSTem:PCARd1 C7700
SYSTem:PCARd2 C7700
SYSTem:PCARd3 C7700
SYSTem:PCARd4 C7700
SYSTem:PCARd5 C7700
Pseudocards for other switching modules can instead be installed. Details on
installing other pseudocards are provided in
<NRf> = slot number (1 to 5)
The Model 2700 uses a different syntax to specify a slot for the :CARD com-
mand. Instead of using the <NRF> parameter, the slot number is included with
the :CARD command word (i.e., SYST:CARD1:VCH:END?). In order to make
the Model 2750 compatible with Model 2700 operation, the :CARD command
for the Model 2750 will accept the 2700 syntax for slots 1 and 2.
Model 2750 Multimeter/Switch System User's Manual
'Install' 7700 pseudocard in slot 1.
'Install' 7700 pseudocard in slot 2.
'Install' 7700 pseudocard in slot 3.
'Install' 7700 pseudocard in slot 4.
'Install' 7700 pseudocard in slot 5.
Section
' Query last volt/Ω2 channel (7700; "20").
' Query last amps channel (7700; "22").
2.
Table 15-7.