VTI Instruments EX1000A, Руководство пользователя

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234 EX10xxA/RX1032/EX1044 Function Calls
vtex10xxA_set_dio_limit_event
F
UNCTION
P
ROTOTYPE
ViStatus vtex10xxA_set_dio_limit_event(ViSession vi , ViInt16 dio_channel ,ViInt16 limit_masks[] );
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.
dio_channel = the channel of the digital I/O port to be linked to limit evaluations. Value must be an integer in the
range of 0 to 7.
limit_masks[] = an array of 48 4-bit integer values representing, on a per input channel basis, the linking of limit
evaluations to any of the 4 limit conditions. Within the 4-bit field, the order of the values is: limit set 0 lower, limit
set 0 upper, limit set 1 lower, limit set 1 upper. The values must be in the range of 0-15 (decimal), 0x00-0x0F (hex).
Channel 0 through channel 47 are represented in array elements [0] through [47], respectively.
D
ATA
I
TEM
R
ESET
V
ALUE
limit_masks[] = 0 in all array elements for all DIO channels
D
ESCRIPTION
This function links limit evaluations to the operation of the digital I/O port. In nominal operation, a DIO channel that
is linked to an input channel’s limit evaluation will transition from low to high whenever the limit is exceeded.
Multiple linkages per DIO channel are allowed and are logically OR’ed together. That is, a DIO channel that is
linked to four input channel limit evaluations will transition whenever any of the four limits are exceeded. Multiple
linkages can be created on the same input channel and/or spanning multiple input channels.
The nominal transition of a DIO channel is from low to high whenever the linked limit is exceeded. Optionally, the
transition can be specified to be from high to low with the vtex10xxA_set_dio_limit_event_invert function.
The nominal operation of a linked DIO channel is to reflect the latest limit evaluation. That is, it will be updated
with every scan. Optionally, the behavior can be set to latch mode with the vtex10xxA_set_dio_limit_event_latch
function . In latch mode, a transition out of the cleared state would remain, regardless of future limit evaluations,
until it is cleared at the beginning of a new acquisition.
E
XAMPLE
// link DIO channel 7 to set 1 lower limits on ch 12 and 14, set 0 upper limit on ch 1
ViUInt16 limit_masks[48] = {0,4,0,0,0,0,0,0,0,0,0,0,2,0,2,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
vtex10xxA_set_dio_limit_event(vi, 7, limit_masks);