IOtech MultiScan 1200, Руководство пользователя

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TempScan / MultiScan User's Manual Chapter 15: Program Examples 249
•
Lines 1-3: Although not necessary, it is good practice to reset the TempScan/1100 at the start of
your application by sending the Reset Power-On (
*R
) command. Wait a few seconds.
•
Lines 4-8: To be certain that the reset was successful and the device is ready, Serial Poll the device
until the proper status is returned.
•
Lines 9-10: The Configure Channels (
C
) command will be used once to configure a range of
channels from 1 to 32 as Type T thermocouples, and used again to configure a range of channels
from 33 to 48 as Type K thermocouples.
•
Line 11: The Set Counts (
Y
) command is used to configure the number of scans to take while in
the different acquisition states. In this example, 50 scans will be taken while in the Pre-Trigger
state, 100 while in the Post-Trigger state, and 200 while in the Post-Stop state. The Post-Trigger
count is only valid when the Stop (trigger stop event) is set to Count via the Set Trigger
Configuration (
T
) command. This example does not use Count, so this parameter is ignored.
•
Line 12: The Set Scan Interval (
I
) command sets the time period between scans in hours-minutes-
seconds format. The TempScan/1100 can have two different scan intervals, one for the Post-
Trigger state (acquisition scan interval), and one for the Pre-Trigger and Post-Stop states (normal
scan interval). This example sets up the Post-Trigger , Pre-Trigger and Post-Stop scan intervals to
the same value of 0.1 second (10.0 Hz).
•
Line 13: The Set Trigger Level (
L
) command specifies the channel as Channel 1 at a level of 20
°
C
with a hysteresis of 0
°
C (where the default units is degrees Celsius). This command is relevant
only when the Trigger (trigger start event ) or Stop (trigger stop event) is a channel level, as
specified on the next line.
•
Line 14: The Set Trigger Configuration (
T
) command sets up the Trigger (trigger start event ) and
Stop (trigger stop event) parameters for the acquisition. In this example, the Trigger and Stop are
assigned the rising level and falling level, respectively, of an input channel as specified via the Set
Trigger Level (
L
) command. The Auto Re-arm flag is disabled, so that the TempScan/1100 will
not re-arm itself for another acquisition after the first acquisition is complete. The synchronization
flag is also disabled, so the TempScan/1100 will not re-synchronize itself to the
Trigger point
when the Trigger (trigger start event) begins. When the TempScan/1100 encounters the Execute
(
X
) command, it will be armed and will start the collection of the Pre-Trigger data.
•
Lines 15-22: After the Execute (
X
) command has been received, the TempScan/1100 arms itself
and then waits for the Trigger (trigger start event) of Channel 1 rising above 20
°
C. The IEEE 488
Serial Poll (
SPOLL
) command is used to query the acquisition status of the TempScan/1100. A
SPOLL
value of 2 signifies that Channel 1 has in fact risen above 20°C.
•
Lines 23-28: Using the User Status (
U
) command
U0
to query the Event Status Register (
ESR
), we
now wait until the Acquisition Complete event is reached.
• Lines 29-36: During the acquisition or after the acquisition has been completed, the Acquisition
Buffer can be queried for the data that is available for transfer. The User Status (
U
) command
U6
can be used to query the Buffer Status String, which includes the following eight fields of
information: (1) Number of Trigger Blocks Available, (2) Number of Scans Available, (3) Current
Position of Read Pointer, (4) Time/Date Stamping of Trigger Event, (5) Position of Stop Event
Pointer, (6) Time/Date Stamping of Stop Event, (7) Position of End Scan Pointer, and (8) Status of
Current Trigger Block. For more information on the Acquisition Buffer, see chapter
System
Operation .
This example uses the last parameter in the return string as an indicator of how much data is
available to transfer to the IEEE 488 controller. The function
MID$
extracts 6 characters from the
string
U$
starting at character 8.
•
Lines 37-43: The Read Buffered Data (
R
) command
R1
is used to request the oldest scan from the
unit. Using the variable
UA%
calculated from the previous step, all of the oldest scan data is
transferred to the controller.