Lawson Labs, Inc. - 800-321-5355 or 610-725-9344 - FAX 610-725-9344 - website - e-mail

special notes for users of the
EMF-16

Graphics Software for Win98/ME/NT/2k/XP

A) Basic Operation Instructions
  1) Start software and select COM port for EMF16.
  2) Click the SignOn button to establish communication. The "RUN" LED on the EMF16 will light after successful initialization.
  3) Click Start Scan to begin and Stop Scan to end.
B) Scan Set Up
  1) Pick an internal data rate and remote averaging value. If you are running long, slow tests, 10 Hz is the minimum rate. 10 Hz will also provide the lowest noise. For faster response, we recommend a 60 Hz internal data rate where the line frequency is 60 HZ, and a 50 Hz rate where the line frequency is 50 HZ.
  2) Remote averaging will increase the filtering, but will slow the scanning rate. To get the smoothest data with the smallest data files, increase remote averaging to the largest value that will allow you to scan fast enough. See #4 below for scan rate.
  3) Click SETUP to change the selected active channels. The 16 input channels for the standard EMF16 are shown in the column labeled "0" on the left. The selected active channels must be in a continuous sequence.
  4) Scan types:
    Normal scanning is a compromise between maximum speed and stability. It is often preferred for electrochemistry applications.
    Calibration scan adds two extra channels to each scan and corrects for offset drift. You may want to use some local averaging with a caibration scan to keep the offset correction from adding marginally to the noise. The offset drift is expected to be less than 100 microvolts per degree C, so this correction may be unnecessary in many applications.
    Single-channel scanning allows much higher scan rates on one channel at a time. The maximum scan rate is normally much slower than the data rate. In Single-channel scan mode the two rates are nearly the same. The scan must be stopped before a different single channel can be selected.
  5) The minimum achievable scan interval will be automatically selected. If you wish to scan more slowly, enter the desired (larger) interval.
  6) Click CLOSE to return to the graphics screen.
C) Graphics Set Up
  1) Up to 16 Channels can be plotted at the same time on the single set of axes.
  2) Channels to plot can be selected from among the active sub-channels for any particular input channel. For the standard EMF16, the "MAIN" channel should always be set to 1.
  3) Adding or removing a channel from the plot does not change the scanning sequence or the data logging files. It does change the Autoscaling. Left or right mouse buttons can be used when changing channels to graph. The left button will select or de-select intervening channels. The right button toggles only one channel at a time.
  4) You can set the plus and minus full scale values by directly typing the voltage desired and pressing Enter, or use Autoscale. The horizontal axis timebase can also be changed directly in the same fashion.
  5) Click the Text/Graphic Screen button to toggle between the two presentations.
D) Offsets
  1) Each EMF16 channel has its own small offset associated. To remove these offsets, begin a scan with all inputs active and electrically shorted using the plugs provided. Put the ground switch in the SAFE position. Best results will be obtained with remote averaging set at 8 or above. After a few minutes, click Save offsets. That will force all readings at that time to be zero.
  2) Thereafter, those offset corrections will be stored and used each time you start your software. If you want to redo the offsets, click Save Offsets again.
  NOTICE: If you save offsets inadvertently, or with floating channels, subsequent data may be drastically shifted.
  3) To permanently remove all saved software offset corrections, click Reset Offsets.
E) Other Functions
  1) Check the LOG box to save data to disk. The Data files are placed in the working directory and are named using the date and time. Click the box again to stop the data logging. A new file is created for each Start Scan. Checking and unchecking the Log box during a scan will result in gaps in your log file. Note that the first column in the file is the time stamp.
  2) BAUD can normally be left at 9600. If serial errors occur, or sign on is troublesome, switching to 4800 BAUD will likely fix it.
  3) Gain can be set in powers of 2. The input range is cut in half for each increase in gain. Normal gain is 1 for a range of +/- 5 volts. A gain of 2 gives a range of +/- 2.5 volts, 4 gives +/- 1.25 volts, etc. Scanning must be stopped in order to change the gain.
  4) Local Average is a running average calculated in the host computer. The average array is pre-loaded with the voltages from the first scan. For large averaging values and/or wide scans, you may see a message on your screen that indicates the arrays are being initialized. The textual data on your screen, the graph, and the data files all reflect the averaged values.

-- find out more --
Last Modified 4/2/2004
A little about the
EMF-16

Precision Electrochemistry EMF Interface
The EMF-16 hardware Please browse the web to HERE for more information

OVERVIEW
  The EMF16 is a high-resolution, high input impedance, data acquisition system for electrochemistry applications. It connects to a PC serial port for presentation and storage of EMF data. The bundled software is written by electrochemists for electrochemistry. It allows up to 16 channels of data to be scanned and displayed, and saved to the disk in real time.The EMF16 is built around our proven 24-bit A/D system. The DC specifications are much better than those of most pH meters. Linearity is 0.002% of full scale, input impedance is 10^13 ohms, reproducibility is better than one part per million. BNC connectors are provided for the 16 buffered inputs and for the buffered reference electrode. All inputs are protected against overvoltage. Three measuring modes are selectable via a front-panel switch. Further flexibility is provided through software configuration.
  The EMF16 is supplied as a complete system including the interface box and Windows software, serial cable, power supply and comprehensive manual. A Macintosh version is also available.

  Last Modified 4/2/2004