VTI Instruments EX1000A, User Manual

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EX10xxA Function Calls 261
vtex10xxA_set_user_cjc_enable
F
UNCTION
P
ROTOTYPE
ViStatus vtex10xxA_set_user_cjc_enable(ViSession vi , ViInt32 channels[] , ViInt32 numChannels, ViBoolean
usercjc );
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.
usercjc = a Boolean value indicating whether to enable the user-defined CJC temperature. If this parameter is set to
“1”, this indicates that the user-defined CJC temperature will be used in thermocouple calculations. If set to “0”, this
functionality is disabled.
D
ATA
I
TEM
R
ESET
V
ALUE
usercjc = 0 (for all channels)
D
ESCRIPTION
This function enables or disables the use of a user-defined CJC temperature for the specified channels. If enabled,
the user-defined CJC temperature will be used in the 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. Entry of the
CJC temperature is done through the vtex10xxA_set_user_cjc_temp 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);