Networked eDAQXR/eDAQXR-lite units can be connected in a variety of ways.
Networking Modes: There are two modes that are supported. There is an SXR test configuration option to specify the desired mode. See Test setup > Network mode for more information.
Mode 1 Networking
One eDAQXR/eDAQXR-lite serves as the networked system host (subsequently referred to as the master node), and all other connected eDAQXR/eDAQXR-lite units provide source data to the master node (subsequently referred to as slave nodes). The master node is not defined in the SXR setup file. When the user starts a test on any network node, that node becomes the master node. This allows the user to experiment with CPU load balancing which is discussed later.
The master node is always used to start the test. The master node runs the test engine that processes all input channels, Computed channels and DataModes and drives the run time displays. A single SIE file is generated on the master node only.
The user only needs to communicate with the master eDAQXR/eDAQXR-lite.
All test runs modes (Normal, Cyclic and Remote control) are available in a networked system. If the Remote control run mode is used, the EXRCPU/EXRLCPU IO switch 1 on the master node must be used.
Mode 2 Networking
The primary difference between Mode 1 and Mode 2 from the user point of view is that every node runs a test engine and generates an SIE file. This mode will typically only be used when Mode 1 cannot be used due to CPU processing limitations on the master node, or when there is insufficient SIE file storage space on the master node.
While each node generates an SIE file, the SIE files are logically linked together. When the SIE file is downloaded on the master node (or on any slave node), the system generates a composite SIE file containing all of the data from all nodes. Similarly, if the user deletes an SIE file on any node, the SIE files on the other nodes are also deleted.
NOTE
There is the following restriction on the current offering for Mode 2 networking.
• Channels cannot be shared across the network nodes (i.e., channels defined on any given node
cannot be used on another node for DataMode triggering, use in a computed channel, etc.).
The user interface does not prohibit this. If the user configures as SXR test in this way, the user interface will attempt to start the test run. However, the system will reset on error.
Physical Connection Options: These options are completely independent of the option to use Mode 1 or Mode 2 networking.
Connections with no EX23-R switch: A maximum of three eDAQXR units can be connected. A maximum of two eDAQXR-lite units can be connected.
Connections using one or more EX23-R switches: There is no restriction on how many eDAQXR nodes can be connected.
CPU load balancing (Mode 1): For many applications, the user does not need to be concerned with this issue. However, if the average CPU load of any node exceeds 50%, the user should consider options for balancing the CPU loads across the nodes, which may require some trial and error experimentation. Following are some guidelines.
CPU load balancing (Mode 2): While this is somewhat less of a concern relative to Mode 1 networking, the master node still has the processing overhead for interacting with the user interface and running the display charts. As such, the suggestions above for Mode 1 networking are still applicable.