Synchronization Options for Multiple cDAQ Chassis With the NI 9469


This tutorial describes the options for synchronizing multiple cDAQ chassis using the NI 9469 Chassis Synchronization Module.


There are two configurations: Star or Daisy-Chain


When all the slave chassis are connected to the master chassis

Figure 1: NI 9469 Star Configuration Example

When using the attached examples in a Star configuration, make sure the first analog input task is the master. The order of the remaining analog input tasks is not important.

Note: There may be more than one NI 9469 in a chassis and the Master module can route its clock out of any and all additional NI 9469's in the Master chassis

Daisy Chain

When the master chassis is connected to slave 1 and slave 1 is connected to slave 2 in a Daisy-Chain configuration.

Figure 2: NI 9469 Daisy Chain Configuration Example

For the above diagram, cDAQ1 is the master chassis connected to cDAQ9188 (slave 1). cDAQ9188 is connected to cDAQ2 (slave 2).

When using the attached examples with a daisy-chain configuration make sure the first Analog task is the master, the second task slave 1, and the third task slave 2.

Notes on Attached Example Code

The attached examples are for Delta Sigma C Series Modules and SAR ADCs / Slow Sampled Modules.*  The SAR ADCs / Slow Sampled modules can be used in Star or Daisy-Chain configurations.  The Delta Sigma Modules can only be used in a Star configuration with NI-DAQmx 9.6.  NI-DAQmx 9.6.1 and later versions add support for Daisy-Chain configurations with Delta Sigma Modules.

Figure 3: Front panel of the attached NI 9469 Delta Sigma Modules example VI.

For more information regarding which C Series modules are Delta Sigma Devices, see the C Series Device Groupings topic in the NI-DAQmx Help.  Note that modules with 16-bit Simultaneous SAR ADCs are not listed (ie: 9215, 9222, 9223).  Other modules with SAR ADCs are listed under Scanned Devices