Chapter 5 Programming© National Instruments Corporation 5-9 SCXI-1120 User ManualSingle-Module Multiplexed Scanning (Direct)To perform simple channel scanning, you must cable the SCXI-1120 to a data acquisition board.See Chapter 2, Configuration and Installation, for more information.To program the module for scanned-channel measurements, write the binary pattern 10XXXCCCXX001101 to the SCXI-1120 Configuration Register. CCC represents the starting channelnumber.Single-Module Multiplexed Scanning (Indirect)To indirectly scan a module, send the output of the scanned module onto Analog Bus 0, where itis picked up by another module and transmitted to the data acquisition board.Channel Scanning from Other Modules. To scan measurements from other modules, you mustcable the SCXI-1120 to a data acquisition board. See Chapter 2, Configuration and Installation,for more information. The module programming steps are as follows:1. Perform any necessary programming to ensure that no modules are driving Analog Bus 0.For an SCXI-1120, clearing AB0EN in the Configuration Register will ensure that its outputis not driving AB0.2. Write the binary pattern 10XXXXXX XX100011 to the SCXI-1120 Configuration Register.This step disables the SCXI-1120 from driving Analog Bus 0 and allows Analog Bus 0 todrive MCH0 through the output buffer.3. Program the other module to be scanned.Channel Scanning from the SCXI-1120 via Another Module. To scan the SCXI-1120 via othermodules, you must cable the other module to a data acquisition board, and the other module mustbe able to transfer Analog Bus 0 to the data acquisition board. The other module must also beable to send a SCANCLK*-compatible signal on TRIG0. See Chapter 2, Configuration andInstallation, for more information. The module programming steps are as follows:1. Perform any necessary programming to ensure that no modules are driving Analog Bus 0.For an SCXI-1120, clearing AB0EN in the Configuration Register will ensure that its outputis not driving AB0.2. Program the other module not to drive Analog Bus 0, but to send Analog Bus 0 to the dataacquisition board. Also program the other module to send a SCANCLK*-compatible signalto TRIG0.3. Write the binary pattern 01XXXCCC XX001111 to the SCXI-1120 Configuration Register,where CCC is the starting channel number.Multiple-Module Multiplexed ScanningTo scan multiple modules, you must connect one module to the data acquisition board, and themodule must be able to transfer Analog Bus 0 to the data acquisition board. This module must