VTI Instruments EX1401, User Manual

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EX1401 Basic Operation 37
S
ECTION
3
B
ASIC
O
PERATION
I
NTRODUCTION
This section expands on the description of the EX1401’s features and explains how to best use them.
E
NGINEERING
U
NIT
(EU) C
ONVERSION
Each EX1401 input channel can be individually configured for measuring thermocouples or voltage.
The following thermocouple types are supported:
Voltage The instrument will return the raw voltage measured at its input
with units of volts (V). It is unaffected by the measured or input
CJC temperature for that channel.
Type J, K, T, E, S, R, B, N The instrument will return the compensated thermocouple
temperature measured at its input with units of temperature (ºC or
ºF). The thermocouple calculations are performed using the full-
order polynomial equations and coefficients from the NIST ITS-
90 Thermocouple Database.
Custom The instrument will return the compensated thermocouple
temperature measured at its input with units of temperature (ºC or
ºF). The thermocouple calculations are performed using user-
defined coefficients for the polynomial equations. More
information on this is given under
User-defined Conversions . The
custom coefficients can be unique for each channel.
The default selection is voltage.
NOTE In a mixed thermocouple system, it is very easy to accidentally mismatch the hardware setup
and the software configuration setup. Care is especially warranted, as the resultant errors
may not be large enough to obviously indicate a problem, but may be significantly larger than
the accuracy specification of the instrument.
Linear Correction
The EX1401 provides the capability to apply a linear transformation on voltage-mode measurement
data after EU conversion. Each channel can be programmed with a gain and offset which are applied
as (gain*data) + offset.
Gains default to 1.0 and offsets default to 0.0.