RM-26999 Getting Started Guide

Overview

This getting started guide, accompanied with the RM-26999 User Manual, is designed to help select the correct components, safely connect those hardware components, install the necessary software, and run the first measurement for a power measurements system built around the RM-26999. There are also a few sections describing the new VIs and examples that were created to accompany the RM-26999 API.

Contents


Figure 1. RM-26999 Example System with DaniSense Current Transducers


Selecting the Right Components


First a PXI Chassis and Controller

In a PXI system, a chassis provides power, cooling, and a communication bus for modular instruments or I/O modules – like the data acquisition device necessary for building a system with a RM-26999. You can control these modules from either an embedded controller or an external PC, using one or several of NI's specialized engineering software tools to customize your system. There are many options and configurations for both chassis and controllers. Feel free to use this page to learn a little more about factors to consider before choosing for your application.


RM-26999 - Power Measurements Conditioning Terminal Block

The RM-26999 is a rack mounted, signal conditioning device that connects to several NI simultaneous multifunction input/output (SMIO) modules and devices for power measurements. The RM-26999 features four voltage input channels, up to 2,000 V peak, and four current transducer ports for current measurements – enabling four power measurements per RM-26999. The RM-26999 is an extremely capable device, but there are a few more components to get the device up and running. Please see below for the necessary components and a short description for each.

Figure 2. (Top Image) RM-26999 Front | (Bottom Image) RM-26999 Back



Data Acquisition Module or Device

The RM-26999 safely conditions the high voltage input paths as well as powers, communicates, and reads the output signals from the appropriate current transducer. A simultaneous data acquisition module or device must be used in conjunction with the RM-26999 to digitize the data. Because the data acquisition device can be chosen separately from the RM-26999, there are several options that include sampling rates of 1.25 MS/s/ch to 3.5 MS/s/ch. The recommended devices upon release are the PXIe-6356, PXIe-6366, and PXIe-6376. If the application requires more than four power channels, two RM-26999 devices can be connected to 16 channels simultaneous data acquisition devices such as: PXIe-6358, PXIe-6368, and PXIe-6378. If an application requires more than eight power channels, multiple PXIe simultaneous data acquisition devices can be tightly synchronized, and easily through channel expansion, to create a flexible and powerful measurement solution.

 

Figure 3. PXIe-6366 – an example 2 Ms/s/ch simultaneous multifunction I/O (SMIO) that can be used as the digitizer with the RM-26999


Connecting the RM-26999 and the Simultaneous DAQ Device

Connecting the RM-26999 to the simultaneous DAQ module only requires a single cable, the SHC68-68-EPM. The SHC68-68-EPM is twisted pair and shielded cable designed to provide optimal performance and accuracy for many of the MIO data acquisition products in the NI data acquisition portfolio. The SHC68-68-EPM can be purchased in a variety of length options, from 0.5m to 10m, and this distance should be the front of the RM-26999 to the front of the data acquisition device within the rack. Please note when measuring high power systems, it is always advantageous to keep wire and cable lengths as short as possible.


Figure 4. SHC68-68-EPM cable that connects the simultaneous MIO device to the front of the RM-26999


Powering the RM-26999

The RM-26999 does need an external power supply to function, it does not draw enough power from the data acquisition device for all functionality. NI recommends that a NI PS-15 or NI PS-16 is purchased with any RM-26999 device for the appropriate amount of power. If another 24V DC power supply exists in your system and it can provide 150W to the RM-26999, this can be used and a NI PS-15 or NI PS-16 is no longer necessary.

Figure 5. PS-15 Power Supply – an example 24V power supply for the RM-26999


Necessary Components for the Current Measurement

As stated above, the RM-26999 does not directly measure current; however, it does support quick connectivity to the very stable, isolated, and accurate DaniSense current transducers. The first step is to identify the correct current range needed for the application and if a voltage output or a current output is desired.



Current Transducers (Voltage Output)

NI offers four models of DaniSense’s isolated current transducers with voltage output. The models offered have measurement ranges of +/- 50A, +/- 200A, +/-600A, and +/-2000A and they require a power supply, digital communication, and output signal lines. The RM-26999 was designed with these sensors in mind, and because of that only a single cable is necessary to connect the RM-26999 to the DaniSense transducer. The SHDB9M-DB9F-BNCM Cable, offered in 2m, 3m, and 5m lengths, were designed to withstand the harsh environments that surround power electronics, provide power to the transducer, and bring back the voltage output of the current sensor to the RM-26999. There should be one cable per each voltage output, current transducer with a maximum of four cables (four transducers) per RM-26999.

Figure 6. Products required to measure current with voltage output transducers and the RM-26999: (left) SHDB9M-DB9F-BNC cable and (right) DaniSense current transducer – voltage output


Current Transducers (Current Output)

NI does not offer the current output versions of the DaniSense transducers but the available options can be researched and purchased through DaniSense at their website. Although these sensors are not available for purchase through NI.com (http://www.ni.com/en-us/shop.html), the RM-26999 does support these transducer types and there are accessories available to easily connect these transducers.


In order to correctly measure the output of these transducers a cable, the SHDB9M-DB9F, and a shunt resistor, SHDB9M-DB9F-Shunt, to scale the output are required. Like the SHDB9M-DB9F-BNCM, the SHDB9M-DB9F offers the same 2m, 3m, and 5m length options and it was designed to be used with these transducers in electrically noisy environments. The DSUB to DSUB shunt resistors are used to accurately convert the output current of the current transducers to a voltage for the RM-26999. The shunt resistor is placed in line with the sensor cable and the RM-26999 current transducer port. There should be one shunt resistor selected per current output current transducer.

Figure 7. Products required to measure current with current output transducers and the RM-26999: (left) SHDB9M-DB9F cable, (middle) SHDB9M-DB9F-Shunt, and (right) DaniSense current transducer – current output


The SHDB9M-DB9F-Shunt is offered in 0.5Ω, 1Ω, 2Ω, 5Ω, and 10Ω options and the shunt value should be chosen by ensuring the data acquisition device input never exceeds 10V. The calculation to help choose the shunt value is shown below.

Figure 8. Equation to help choose the right SHDB9M-DB9F-Shunt value based on the expected current measured and the current transducer scaling



Safety Note – Follow the User Manual for Setup


Above, we have all the information to help us choose the right equipment for an application with the RM-26999. At this point we are ready to put everything together and start making measurements. Due to the power levels associated in these applications, please refer to the RM-26999 User Manual on properly and safely connecting these components with a high power system.




Software Requirements


To operate a RM-26999 a couple different software pieces are required. Please note, as stated in the manual, these should be downloaded and installed in the following order:


  1. LabVIEW 2015 or or later
    • NOTE: the RM-26999 is not currently supported in LabVIEW NXG
  2. NI-DAQmx 15.0 or later
    • Make sure the NI-DAQmx version supports the chosen LabVIEW version
  3. RM-26999 API
    • This requires the VI Package Manager
      • For more information about the VI Package Manager, please see the VI Package Manager Whitepaper
      • VI Package Manager should install with LabVIEW, if needed here is the download location from JKI.
    • Search for (top right corner of VI Package Manager) and double click on RM-26999 to install the API



Identifying a Connected RM-26999


After completing all hardware and software installation processes, it’s time to ensure the RM-26999 can be identified on your PXI controller or PC. Please note, unlike many NI products, the RM-26999 will not be visible in NI MAX. Despite this, we have created a specific utility to ensure all connected RM-26999s can be identified.


  1. In LabVIEW, navigate to the Help >> Find Examples… to open the NI Example Finder
  2. Make sure to browse the example finder by the directory structure.
  3. Navigate to the NI >> RM-26999 folder and double click RM-26999 Device Enumeration.vi
  4. Once the VI is open follow the instructions in the top left corner to successfully identify your device. A successfully identified device should look like this.

Figure 9. RM26999 Device Enumeration.vi example showing a successful identification of a RM-26999 connected to a system




Taking the First Power Measurement


On to the first power measurement (click here for other examples included). Included with the RM-26999 API installed are a group of examples and to find them follow the same steps from above:


  1. In LabVIEW, navigate to the Help >> Find Examples… to open the NI Example Finder
  2. Make sure to browse the example finder by the directory structure.
  3. Navigate to the NI >> RM-26999 folder and double click RM-26999 Continuous Power Acquisition.vi
  4. Once the VI is open the recommendations for running the VI can be found by pressing <CTRL> + H and hovering over the VI icon in the top right-hand portion of the VI.


Figure 10. Navigation steps to find the RM-26999 API Example VIs in NI Example Finder



Please note, the RM-26999 Continuous Power Acquisition.vi example uses power analysis algorithms for single phase power analysis implemented in the same manner as the Electrical Power Toolkit available today. More advanced 3-Phase power analysis algorithms are coming soon please contact you account manager for additional information.



Figure 11. Screenshot of fully operational RM-26999 system running on the RM26999 Continuous Power Acquisition.vi example



RM-26999 Example Descriptions


The following examples have been developed specifically to interface with the RM-26999 and the recommended accessories, such as the DaniSense current sensors. Although these example VIs are likely not a complete measurement application, they are designed to showcase several features of the RM-26999 and provide higher level starting points with commonly used functionality.



RM-26999 Continuous Power Acquisition DaniSense Sensors.vi
This example is designed to acquire continuous voltage, current, and single-phase power measurements with the RM-26999 and DaniSense sensors. This example includes the option to log the data acquired and remotely monitor the hazardous voltage and current transducers status LEDs.


RM-26999 Continuous Power Acquisition.vi
This example is designed to acquire continuous voltage, current, and single-phase power measurements with the RM-26999 and current sensors. This example includes the option to log the data acquired and remotely monitor the hazardous voltage and current transducers status LEDs.


RM-26999 Current Acquisition Voltage Output Sensors.vi
This example is designed to acquire continuous current measurements with the RM-26999 and current sensors that output a voltage for the measured signal. This example includes the option to log the data acquired.


RM-26999 Current Acquisition Current Output Sensors.vi
This example is designed to acquire continuous current measurements with the RM-26999 and current sensors that output a current for the measured signal. This example includes the option to log the data acquired.


RM-26999 Current Sensor Scaling.vi
This example is used as a subVI in several RM-26999 examples. This is designed to convert the attributes from the current sensor specifications to the scaling factor expected by the RM-26999 API VIs.


RM-26999 Device Enumeration.vi
This VI can be used to identify, both visually and in software, all connected RM-26999 devices to the machine running the RM26999 Device Enumeration.vi.


RM26999 Voltage Acquisition.vi
This example is designed to acquire continuous voltage measurements with the RM-26999. This example includes the option to log the data acquired.




RM-26999 API Descriptions


The RM-26999 API, built with LabVIEW, is designed specifically with the functionality of the RM-26999 and the NI-DAQmx code that will be used along with it. The 21 VIs that make up the API are divided into groups of functionality: the top level RM-26999 calls, power measurements, advanced, and calibration. Below are short descriptions for some of the groups, please see the RM-26999 VI Reference documentation for the complete documentation for each VI. To get to the documentation open LabVIEW, navigate to Help >> RM-26999 VI Reference … , and a new window with the documentation will open.


Figure 12. RM-26999 API Palette in LabVIEW

Top Level VIs
The top level VIs within the API will be the VIs most commonly used. These VIs are used, in conjunction with the NI-DAQmx VIs, to initialize the RM-26999 voltage channels, initialize the RM-26999 current channels, and close the session to the RM-26999.


Power Measurement VIs
The power measurement VIs are built to give the first layer of analysis for power electronics applications. Fundamental frequency analysis, RMS, single phase power, and single phase energy calculations are all included. NI is actively developing more analysis for power electronics applications, for more information please contact your account manager.


Advanced VIs
The advanced VIs within the palette provide the ability to read important information and statuses from the RM-26999 itself or the connected accessories (if supported). Examples of information that can be read from the RM-26999: device calibration, device temperature, power supply status, if any voltage channels are hazardous (50 V DC or 40 V AC 60 Hz on an input channel), or the current sensor status. These functions can be extremely helpful to learn about the state of the device without physically inspecting the queried RM-26999.