A Commander has exclusive control of the communication and configuration registers of its immediate Servants one or more. By choosing a PC-based MXI approach, you are choosing to add value to your VXI instrumentation systems by using technologies that make sense from both a cost and performance perspective. Type of controller or controller configuration. PXI devices are automatically recognized by the operating system. It uses a single pulse on one trigger line and is asserted low. Stub lengths no more than 4 in. Set “allocate on-board memory”, Set number of scans to acquire.

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For low-level register access, use the Peek and Poke methods.

This site uses cookies to offer you a better browsing experience. This configuration is functionally equivalent to the embedded method, except that it has the flexibility for use with a wide variety of computers and workstations.

VXI – National Instruments

This benchmark lavbiew easy for vendors to isolate and measure under ideal conditions. In fact, many of the largest instrument suppliers in the world are members of both organizations, including National Instruments, GenRad, Hewlett-Packard, Racal Instruments, and Tektronix.

These devices are interlaced by mapping together portions of their individual address spaces so that a system composed of multiple devices behaves as a single system with a shared address space.

Raw computing power can be the single most important consideration for the performance of your system. An MXI-equipped computer is functionally equivalent to an embedded computer. This is accomplished by selecting “VXI DAQ” from the list of common hardware configuration settings labvieww the controller s.

NI-VXI and VXI Controller Support

For lower channel counts, consider using a front panel terminal block, SCC modules, or a SC adapter board that allows you to attach additional signal conditioning accessories.


Users can have several DAQ modules all acquiring data at maximum capacity until each module fills labfiew 64 MB max memory and then get the data from the RAM when the system is not busy.

Since that time, the Consortium has defined system-level components required for hardware interoperatibility. If you want your program to respond to any of the following conditions, define event procedures for the appropriate event: From a system standpoint, this means that MXI throughput rates can easily keep up with the data rates of high-performance computers, peripherals, and instrumentation.

Although traditional connectivity solutions have proved to be very effective, they also have proved to be the bottleneck in VXI test systems because the software protocol overhead associated with these methods significantly reduced the ,abview throughput on the link.

Figure 7 shows the MXIbus hardware memory-mapped communication. It does not measure how fast the computer can process the blocks of data or store them to disk once they are moved, or whether your instruments themselves can actually match that data rate. To help meet these requirements, the VXIbus module width was increased from the 0. Word Serial communication is paced by the bits in the response register of the device, indicating whether the Data In register is empty and vi the Data Out register is full.

The In methods have two parameters: For example, you lagview want to open a VISA session when users click on an Open Session button on the front panel, as in the following event procedure: The MXIbus is a powerful, high-speed communication link that interconnects devices using a llabview cabling scheme. There is an additional protocol that can be useful, although it is not presently defined in the Rev.


From this property page, you can write and read message-based commands. Internally labciew are 48 single-ended, twisted-pair signal lines. The VMEbus standards defined a high-performance bus for test systems, but it did not cover the issues of timing and synchronization.

Figure 3 shows one way you might configure communication settings. The onboard processors that implemented parsing in the VXI modules standard message-based communication did not keep up with the bandwidth available in VXI. Then you could be assured that any code written for your instrument is portable across controller vendors as well as operating systems. The string might look something like WFM3. In addition, this circuitry also detects external remote MXIbus cycles of connected devices whose addresses map into the shared memory space of the overall system.

MXI-2 features an improved cabling scheme that uses a single double-shielded cable between all devices, and a single high-density, high-reliability pin connector per device. The VXIbus specification has a tutorial section on how to design a backplane for low noise and high signal integrity.

With the ASRL setting, you labviee communicate with your instrument as you would any other message-based device, as in the following example: Notice the response that appears in the String received indicator.