IOtech MultiScan 1200, User Manual

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TempScan / MultiScan User's Manual Chapter 15: Program Examples 267
The following program is
BIN_HLL.BAS
in the
\EXAMPLES\
subdirectory. It will configure 24
thermocouple and 12 volts channels, set up the MultiScan/1200 for acquisition, and then after the
acquisition is complete, collect the High/Last/Low (HLL) channel readings in a Binary format rather
than the default ASCII format. The Binary format is inherently faster than ASCII format, but the data
must be deciphered after it is collected in order to yield the temperature values.
•
Lines 1-3: Although not necessary, it is good practice to reset the MultiScan/1200 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 first thing necessary to start scanning is to setup the measuring mode. In this case,
the MultiScan/1200 will be setup for line-cycle integration / high-speed multi-channel mode.
•
Lines 11-12: The Configure Channels (
C
) command will be used once to configure a range of
channels from 1 to 24 as Type J thermocouples, and used again to configure a range of channels
from 25 to 36 as 10-Volt DC inputs.
•
Lines 13-31: For sample acquisition program lines, refer to the previous MultiScan/1200 program
example. For convenience, lines 13-31 from that example are identical to lines 13-31 in this
example.
•
Line 32: Before reading the data, the Set Data Format (
F
) command is sent, instructing the
MultiScan/1200 to return the data in Binary format where every value will be 2 bytes in length.
This command can be issued anytime after the initial reset, and stays in effect until the unit is reset
again or another
F
command is issued.
•
Lines 33-40: This example will now use DMA (Direct Memory Access) to transfer the HLL data
into the controller. For this purpose, an array is dimensioned, then the offset and segment pointers
are supplied to the IEEE 488 driver. After the
ENTER
command has completed, the Binary data
will be in the string
READS
.
•
Lines 41-61: To convert the data into integer form, the string must be parsed and decoded.
•
Lines 62-63: To convert the integer data into temperatures and into voltages, simple calculations
are performed.