Custom EU Conversion Tables
The HP E1313/E1413 provides for loading custom EU conversion tables.
This allows you to have on-board conversion of transducers not otherwise
supported by the HP E1313/E1413.
Standard EU Operation
The EU conversion tables built into the HP E1313/E1413 are stored in a
“ library” in the module’s non-volatile Flash Memory. When you link a
specific channel to a standard EU conversion using the
[SENSe:]FUNCtion:
…
command, the module copies that table from the library to a segment of RAM
allocated to the specified channel. When a single EU conversion is specified
for multiple channels, multiple copies of that conversion table are put in RAM,
one copy into each channel’s Table RAM Segment. The conversion
table-per-channel arrangement allows higher speed scanning since the table is
already loaded and ready to use when the channel is scanned.
Custom EU Operation
Custom EU conversion tables are loaded directly into a channel’s Table
RAM Segment using the
DIAGnostic:CUSTom:LINear
and
DIAGnostic:CUSTom:PIECewise
commands. The
DIAGnostic:CUSTom:
…
commands can specify multiple channels. To “ link” custom conversions to
their tables you would execute the
[SENSe:]FUNCtion:CUSTom
<
range
>,(@<
ch_list
>)
command. Unlike standard EU conversions, the
custom EU conversions are already linked to their channels (tables loaded)
before you execute the
[SENSe:]FUNCtion:CUSTom
command but the
command allows you to specify the A/D range for these channels.
Note
The
*RST
command clears all channel Table RAM segments. Custom EU
conversion tables must be reloaded using the
DIAGnostic:CUSTom:
…
commands.
Custom EU Tables
The HP E1313/E1413 uses two types of EU conversion tables, linear and
piecewise. The linear table describes the transducer’s response slope and
offset (y = mx + b). The piecewise conversion table gets its name because it
is actually an approximation of the transducer’s response curve in the form
of 512 linear segments whose end-points fall on the curve. Data points that
fall between the end-points are linearly interpolated. The built-in EU
conversions for thermistors, thermocouples, and RTDs use this type of table.
Custom Thermocouple
EU Conversions
The HP E1313/E1413 can measure temperature using custom characterized
thermocouple wire of types E, J, K, N, R, S, and T. The custom EU table
generated for the individual batch of thermocouple wire is loaded to the
appropriate channels using the
DIAGnostic:CUSTom:PIECewise
command.
Since thermocouple EU conversion requires a “ reference junction
compensation” of the raw thermocouple voltage, the custom EU table is
136 Understanding the HP E1313/E1413
Chapter 4
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