The Data Logger CVF2 Details



Portability combined with industrial robustness and accuracy are the key features that put the Data Logger CVF2 in a class by itself. A light-weight, stand-alone device, the CVF2 can be connected to instruments anywhere in an industrial environment to measure voltage, current and frequency signals. Built-in , heavy-duty electrical isolation protects it from voltage extremes and the CVF2's 16 bit resolution generates highly accurate measurements.

These features make the CVF2 an ideal device for a wide range of applications, including:

  • commissioning and optimization of automation equipment and instrumentation;
  • maintenance, calibration, quality assurance, and diagnostics of electronic equipment and instrumentation;
  • process control tuning and optimization;
  • process audits; and
  • signal analysis.

  • Analyse-Plus Software

  • Portability
  • Battery Backup and External DC Source
  • Industrial Robustness Through Isolation
  • High Resolution and Accuracy
  • Anti-Aliasing Filters
  • Sophisticated Collection Triggering
  • Simple Connection and Operation
  • Stand-alone Operation
  • Large Data Collections
  • One Complete Integrated Package
  • If you don't have a Parallel Port...
  • Computer System Requirements
  • Specifications

  • Portability

    The Data Logger CVF2's portability is the result of its design as a stand-alone microprocessor-based unit that connects directly to your PC's parallel port. Unlike most data acquisition products which employ a plug-in card which must be installed in your computer, the CVF2 does not use any plug-in card. All of the electronics exist in the CVF2 unit itself and communication/transfer of data to your computer occurs through a standard straight-thru cable (included). In fact, there are no jumpers or switches to set anywhere. Since most portable computers do not have empty expansion slots, plug-in card systems are not usually portable. The CVF2 uses the computer's parallel port instead of a plug-in card, and so is ideal for use with a portable computer.

    Battery Backup & External DC Source

    Leds The CVF2 includes a built-in rechargeable battery capable of powering the unit for 10 hours. A status LED indicates when battery power is in use and when the battery is low. When power is restored, the battery is automatically recharged. In addition, with the optional plug, an external DC supply can be connected (18 to 25 VDC for units sold after Jan 1, 2009, 11.5 to 25 VDC for older units).

    Industrial Robustness Through Isolation

    The CVF2's industrial robustness comes from its built-in electrical isolation. Each channel is isolated to 1500 VDC with 300 VDC overvoltage protection. (See Specifications). Conventional unisolated systems typically protect to only 30 V. In industrial applications, any user can accidentally connect to an incorrect signal -- possibly higher voltages. Without isolation, this could result in damage to the data acquisition device, including other channels, damage to the user's computer, and damage to the instruments providing the signals measured on other channels. In fact, your process or experiment could be upset or damaged, resulting in expensive downtime. The CVF2's isolation will prevent this otherwise inevitable accident.

    High Resolution and Accuracy

    The CVF2 uses a 16 bit A/D converter which gives it 16 times more sampling resolution than the 12 bit A/D's used in most data acquisition equipment. Additionally, the CVF2 has automatic software linearization, factory set for each unit shipped, to minimize the non-linearity inherent in each A/D chip. The CVF2 also has "gain" and "zero" calibration values, factory set for each range and stored in its on-board EEPROM. When the user selects a range, these gain and zero values are automatically used without user intervention. The CVF2 also has the ability to perform automatic self-calibration with a user-supplied reference signal. (Due to lack of demand, we no longer include the calibration software in Analyse-Plus). However, with the CVF2's 0.0015 % of scale resolution and its high accuracy, you may be using the CVF2 to calibrate other instruments.

    Anti-Aliasing Filters

    The Data Logger CVF2 is equipped with a 4-pole 500 Hz analog (hardware) filter to remove frequencies before sampling at 1 msec intervals. To achieve the user's sample period of n msec (where n is at least 1), the Data Logger sub-samples the digital 1-msec samples. Prior to this sub-sampling, the Data Logger applies a digital anti-aliasing filter to minimize aliasing. You can choose the the time constant or cut-off period of this filter.

    With both the hardware and software filters in place, aliasing is one thing you won't have to worry about.

    Sophisticated Collection Pre & Post Triggering

    You can specify a complex set of criteria which when met, will cause the CVF2 to start collection. A criterion is met when a signal amplitude falls within/outside of pre-selected amplitude band. Up to 3 channels can be specified with an AND, OR, SEQUENCED, or LATCH linking them. For example, you can specify that the collection should begin x milliseconds after a flow is below 20, a pressure is above 80 and the pump is turned on. You can also delay a collection in intervals of 1 msec up to several days or use the triggering in combination with a delay. These are examples of post-triggering.

    With pre-triggering,, you can start a collection before the trigger criteria were met. For example, in the case above, you could start the collection before the process conditions occurred so that you can determine the cause. The pre-trigger advance time can be set in intervals of 1 msec. Samples collected during the advance time are buffered in the Data Logger's RAM so the maximum advance time depends on the available RAM (this is a function of the sample period and number of active channels).

    The trigger criteria is always checked every millisecond, regardless of the collection sample period.

    You can also use Auto-Retrigger to restart a triggered collection as soon as the current collection has ended. The CVF2 will start looking for your Collection Triggering Criteria in the following millisecond. This process will be repeated until you stop it.

    Both pre and post triggering can be used in stand-alone mode (see below) if Auto-Retrigger is off.

    The green COL LED pictured above right will flash slowly when the Data Logger is waiting for the criteria to be met, will flash slowly when the post-trigger delay is active and will stay on when normal data collection is occurring.

    Connection Drawing

    Simple Connection and Operation

    Weighing only 5 lb (2.5 Kg), the CVF2 can be easily hand carried to any location. Connection is simple. Just plug one end of the included parallel cable into the CVF2 and the other end into the computer s parallel port. Then connect the signals you want to measure, directly to the terminal strip on the CVF2. You can connect up to 9 signals to be measured simultaneously -- 8 analog signals and 1 frequency (pulse counter) signal. Among the 8 analog channels, you can connect voltage or current signals to any channel. Separate inputs on the terminal blocks differentiate the high impedance voltage inputs from the low impedance current inputs. Connect the adapter to a 115 VAC source (or 230 VAC with optional substitute adapter). If there's no power Connection Photo close at hand, let the built-in battery power it. Turn on the CVF2 and the computer and run the included software. Setup the channel inputs directly through the software -- all ranges/gains, voltage/current selection and frequency channel trigger levels are entirely software selectable from a pop-down list. Or, look up your tag in the tag data base (if you've collected from it before) and let the computer set up everything. When you re ready to start collection, just click START.

    Unlike many other data acquisition products, there is no programming to do. You only need to run the included Setup program to install Analyse-Plus Collection and Analysis Software onto your hard disk. The Data Logger CVF2 is then ready to use.

    Stand-alone Operation

    After you've started a collection, you can disconnect your computer if you wish and perform other work. Or you can connect to another CVF2 unit, or do some printing through the CVF2's print-thru port. How is this possible? The CVF2 has its own microprocessor and on-board RAM memory. Once you've given it instructions on what to collect, the CVF2 continues the collection without the need of the computer. The CVF2 also saves whatever information you have entered to document your work such as tag variable names, descriptions and general comments. A status LED illuminates when your collection is finished.

    This stand-alone mode capability offers many advantages over conventional data acquisition equipment. Firstly, you only need one computer even if you are using several CVF2 units. Secondly, if you are performing a long collection, you can free that computer for other tasks. You may simply want to remove your computer because it is in a hot, dusty, or otherwise hostile environment. You can print reports or documents or data previously collected by the CVF2 using the print-thru port to a printer, even while the CVF2 is collecting. The included software allows you to plot, view, analyse, edit, filter, and print previously collected data, while you independently perform a collection.

    Stand-Alone mode is possible with a normal, pre-triggered or post-triggered collection if the total number of samples you are collecting fits in the CVF2's memory and you are not using Auto-Retrigger.

    Large Data Collections

    The CVF2 divides its on-board memory amongst the channels you are using. It can hold 242688 samples in memory. For example, if you are using 4 channels, you could collect 60672 samples per channel and still use Stand-Alone Mode (as long as you are not also using Auto-Retrigger as explained above).

    If you don't need to collect in Stand-Alone Mode, you can collect a virtually unlimited number of samples in a single collection (4 billion per channel). In this type of collection, you keep the computer connected to the CVF2 and Analyse-Plus continuously saves the data to your hard disk as it is collected.

    To keep the file sizes reasonable, the data from each channel is saved in a single file, up to 250,000 samples per file. If you collect more than this, new files are automatically created. You can reduce this limit if a smaller size is more convenient.

    One Complete Integrated Package

    We supply portability, isolation, plotting and analysis software, voltage, current and frequency measurement and battery backup. With other manufacturers, those options that are available are normally priced at an additional 100 to 200 % of the price of the basic unit. The customer then receives a system consisting of several hardware units connected by cables. This configuration reduces the portability of the system, while increasing the setup time, human error and susceptibility to electronic noise and failure. The CVF2 offers all of the above items in one single portable isolated unit at a competitive price. We also provide a two year limited warranty and one year of unlimited technical support.

    Computer System Requirements
    A Few of Our Customers

    Top of page