Keithley 2001-TCSCAN Instruction Manual page 53

Operation
Configure and perform automatic scanning
Remote scanning resembles front panel stepping rather than
front panel scanning. For this reason, the front panel STEP
annunciator is on for remote scanning.
• A trigger is output after every channel is scanned and
measured.
• The time period between scanned channels can be set
using the trigger model Timer or the trigger model De-
lay. When using the Timer, the larger of the time peri-
ods (Timer or Delay) is in effect for scanning.
Add the following statements to the program to configure
and perform two scans of six channels.
Channel 1 is included in the scan list be-
cause the reference junction temperature
needs to be acquired to assure measure-
ment accuracy for the temperature mea-
surement channels (2 through 6).
PRINT #1, ''output 02; init:cont off''
PRINT #1, ''output 02; trig:coun 12''
PRINT #1, ''output 02; trig:sour tim''
PRINT #1, ''output 02; trig:tim 0.5''
PRINT #1, ''output 02; rout:scan (@1:6)
PRINT #1, ''output 02; rout:scan:lsel int''
PRINT #1, ''output 02; trac:poin 12''
PRINT #1, ''output 02; trac:feed sens''
PRINT #1, ''output 02; trac:feed:cont next'' '14
PRINT #1, ''output 02; form:elem read,
chan, unit''
PRINT #1, ''output 02; init''
PRINT #1, ''output 02; trac:data?
PRINT #1, ''enter 02''
LINE INPUT #2, A$
PRINT A$
PRINT #1, ''output 02; rout:scan:lsel none'' '21
PRINT #1, ''output 02; rout:open:all''
END
3-24
NOTE
'Comments
'6
'7
'8
'9
'10
'11
'12
'13
'15
'16
'17
'18
'19
'20
'22
'Comments
6 Disables continuous intiation.
7 Sets trigger count to 12 (2 scans of 6
channels).
8 and 9 Selects TIMER and sets it for 0.5 seconds.
This is the delay period between scanned
channels.
10 Configures the scan list for channels 1
through 6.
11 Selects internal scanning.
12 through 14 Configures buffer to store 12 temperature
readings.
15 Includes channel number and temperature
units with readings over the bus.
16 Starts scanning operation.
17 through 20 After the 2 scans are finished, the 12
temperature readings are sent to the
computer where they are displayed.
21 Disables the scanning mode of operation.
22 Opens the last scanned channel (6).
Open and close channels
Manual scanning can be performed by using the
:ROUTe:CLOSe/OPEN commands. The following program-
ming statements used to measure temperature at channel 3
assume the instrument is already configured to make temper-
ature measurements. The previous programming example
configures the instrument to make type K thermocouple tem-
perature measurements (˚F).
Channel 1 (reference junction) needs to be
read often to ensure accurate temperature
measurements.
PRINT #1, ''output 02; :rout:clos (@1)''
PRINT #1, ''output 02; :rout:clos (@ 3)''
PRINT #1, ''output 02; :rout:open:all''
'Comments
1 Closes channel 1 to acquire the reference
junction temperature.
2 Opens channel 1 and closes channel 3. The
temperature for channel 3 is displayed on
the instrument.
3 Opens channel 3.
NOTE
'Comments
'1
'2
'3