VTI Instruments EX1000A, Руководство пользователя

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262 EX10xxA/RX1032/EX1044 Function Calls
vtex10xxA_set_user_cjc_temp
F
UNCTION
P
ROTOTYPE
ViStatus vtex10xxA_set_user_cjc_temp(ViSession vi , ViInt32 channels[] , ViInt32 numChannels , ViReal64
cjc_temp );
F
UNCTION
P
ARAMETERS
vi = contains a session handle to the instrument. This handle is obtained by the function and remains valid until the
session is closed.
channels = an array to receive the requested scan list. Valid input values: 0 through 47.
numChannels = an integer output value indicating how many channels are in the scan list. Valid input values: 1
through 48.
cjc_temp = sets the value of the user-defined CJC temperature. The value is entered with units of ºC, regardless of
the units selection of the input channels. To ensure accuracy, J, K, T, E, and N types should be set to values between
-40 and 75 (inclusive), while B, R, and S types should be set to values between 0 and 75 (inclusive). Any floating-
point number, however, will be accepted by this parameter.
D
ATA
I
TEM
R
ESET
V
ALUE
cjc_temp = 0 (for all channels)
D
ESCRIPTION
This function sets the user-defined CJC temperature for the specified channels. If enabled, the temperature entered
will be used in thermocouple calculations instead of the internally measured one. Each channel can be associated
with a unique value and be independently enabled with regards to its use. The entry of external CJC values and their
enabling are disjoint functions. That is, the entry of a value does not automatically enable its use, and the disabling
of a previously enabled channel does not clear the value. Enabling is done through the
vtex10xxA_set_user_cjc_enable function.
NOTE This function should only be used when the thermocouple cold junction is made external to the
EX10xxA. This feature must be used with care, as the input channel data contains no indication that
it was calculated with an external CJC value instead of an internal one.
E
XAMPLE
// CJC for channels 0-4 are held externally at 0.2 C
ViInt32 ext_channels[5] = { 0, 1, 2, 3, 4 };
vtex10xxA_set_user_cjc_temp(vi, ext_channels, 5, 0.2);
vtex10xxA_set_user_cjc_enable(vi, ext_channels, 5, 1);