VXI VT1422A - Manual (Page 154)

152 Programming the VT1422A for Data Acquisition and Control Chapter 4
Usage Example:
The program puts table constants into array <table_block>
DIAG:CUST:MXB 2.2,19,(@132:163)
send table for chs 32-63
to VT1422A
SENS:FUNC:CUST 1,(@132:163)
link custom EU with chs 32-63
and set the 1 V A/D range
INITiate then TRIGger module
Loading Tables for Non Linear Conversions
The DIAGnostic:CUSTom:PIECewise <table_range>,<table_block>,
(@<ch_list>) command downloads a custom piecewise Engineering Unit
Conversion table to the VT1422A for each channel specified.
•
The <table_block> parameter is a block of 1,024 bytes that define 512
16-bit values. SCPI requires that <table_block> include the definite
length block data header. The VXIplug&play function
hpe1422_sendBlockInt16(...) adds the header automatically. Contact a
VXI Technology System Engineer for more information on creating
piecewise custom EU tables.
•
The <table_range> parameter specifies the range of input voltage that
the table covers (from -<table_range> to +<table_range>). The value
specified must be within 5% of: 0.015625 | 0.03125 | 0.0625 | 0.125 |
0.25 | 0.5 | 1 | 2 | 4 | 8 | 16 | 32 | 64.
•
The <ch_list> parameter specifies which channels will have this custom
EU table loaded.
Usage Example:
The program puts table constants into array table_block
DIAG:CUST:PIEC <table_block>,1,(@124:131)
send table for chs 24-31 to
VT1422A
SENS:FUNC:CUST 1,(@124:131)
link custom EU with chs 24-31
and set the 1 V A/D range
INITiate then TRIGger module
Summary
The following points describe the capabilities of custom EU conversion:
•
A given channel only has a single active EU conversion table assigned
to it. Changing tables requires loading it with a DIAG:CUST: …
command.
•
The limit on the number of different custom EU tables that can be
loaded in a VT1422A is the same as the number of channels.
•
Custom tables can provide the same level of accuracy as the built-in
tables. In fact the built-in resistance function uses a linear conversion
table and the built-in temperature functions use the piecewise
conversion table.