National Instruments SCXI -1125 用户手册

When using a C-based environment, several steps are needed to configure 
the SCXI-1125 for multiplexed scanning. The following procedure outlines 
the steps for programming with the low-level DAQ function calls:

1.

Prepare the SCXI-1125 settings by either loading the original SCXI 
configuration settings using 

SCXI_Load_Config

, or by specifying 

the gain and filter settings using 

SCXI_Set_Gain

 and 

SCXI_Configure_Filter

.

2.

Use 

SCXI_SCAN_Setup

 to specify the module scan list, the start 

channel of each module, and the number of channels to scan on each 
module. 

SCXI_SCAN_Setup

 accepts an array of start channels and an 

array of the number of channels to scan in each module. It is not 
possible to repeat channels or use nonsequential channels using 

SCXI_SCAN_Setup

.

3.

Next, use 

SCXI_MuxCtr_Setup

 to program the E Series DAQ device 

with the correct number of channels multiplexed per scan. This 
number must match the total number of channels programmed in 
step 2.

You are now ready to acquire the channel data with the E Series DAQ 
device. If you are using a multifunction E Series DAQ device, you can use 

SCAN_OP

 to perform the scanning operation. After scanning, convert the 

binary data to voltage data using 

SCXI_Scale

. Refer to the NI-DAQ User 

Manual for additional information on scanning with DAQ devices.

Performing scanning operations in parallel mode requires no special 
channel strings or function calls for setting up channel sequencing as is 
required in multiplexed mode. Scanning the SCXI-1125 channels on a 
differentially configured DAQ device is done as if there were no 
SCXI-1125 module connected. The only requirement is that you must 
configure the module for parallel mode in MAX as described in Chapter 1, 

In LabVIEW, the SCXI-1125 configuration settings are automatically 
passed from MAX. LabVIEW can also set the SCXI-1125 configuration 
parameter, operating mode, to parallel or multiplexed programmatically 
by using the Set SCXI Information VI. In Measurement Studio, set the 
operating mode using MAX as described in Chapter 1,