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Text-based control of the DOMS using HyperTerminal

Through the communication protocol developed by Paul Faerber, one can view or modify the DOMS settings, as well as read the current or stored status of the measurement, simply by a HyperTerminal connection between the DOMS and a PC. Below you can learn how to do it.

Install the communication device

  1. Install USB-Nano-485 drivers on your PC to recognize the device through which the connection with the DOMS can be established (the drivers can be downloaded from here). The communication will take place through a so-called MPI-bus. Plug in the device to the USB port of your PC and note which COM-port was assigned to it. This can be found in the system properties: Hardware→Device Manager→Ports(COM & LPT).

Establish communication

  1. Connect the DOMS with the PC.
  2. Open an application that can send characters to and read characters from the COM port, such as HyperTerminal (Start→Programs→Accessories→Communications→HyperTerminal). Configure the COM port as shown in the figure below, and establish the connection.

View and modify settings

  1. Press enter to see the list of current settings of the DOMS (Fig. 2A). If spec appears in the list, enter spec to see the settings for the acquisition of spectra (Fig. 2B). Enter config to see more parameters and settings (Fig. 2C).
  2. Meanings of the parameters are listed in Tables below.
  3. The tables also give examples of how to change the value of a specific parameter. To do this, just type the listed command and press enter. Note: whenever you type a character, it is registered by the DOMS and echoed back, which is why you always see what you have typed. The specified command is executed after you press the enter key (\r). If the command was understood, the corresponding action is performed and an OK is returned, indicating success. If no OK appears but instead the DOMS status is returned, the enterred command was not recognized or the value of the parameter that you wanted to modify was out of the acceptable range.

Start/stop the measurement

  1. After you have modified all the required settings, you can either
    • enter run to start logging data in a specific interval (see Tables below), or
    • enter auto to start measuring profiles (note: profiles should always start from depth 0, so make sure you set the position to zero right before you start the profile).
  2. Once the measurement has been started, the last measured data line is returned by the DOMS on can be read by any device connected to the MPI-bus. For example, when using the HyperTerminal, the line will be displayed there (Fig. 3).
  3. Enter stop to stop the data logging or microprofiling. Try again if you don't succeed, as it is possible that the command was entered during the “deaf” time, when the DOMS did not listen to the commands on the MPI-bus because it was busy sending the data.

Note: Each profile starts at a position of 0, and is measured at exactly repstepa depths. The profile is divided by two boundaries (A and B), and the motor positions increase in increments of stepa between positions 0 and A, stepb between positions A and B, and stepc from position B onwards. (Naturaly, the motor positions decrease if the increments are negative.) After the signal is read at the last position, the motor moves to the waiting position (posb), where it waits for pauseb seconds, and repeats the profile. After a set of profiles was measured, the motor moves to the stand-by position (posc), where it waits for pausec seconds, and repeats the set of profiles (see Tables below).

Retrieve/clear the recorded data

  1. To retrieve the data from the DOMS, select Transfer→Capture Text in the HyperTerminal, specify the output file and click on start. Then, enter getdata to download the data that was recorded on the DOMS's storage medium from the last deletion, or enter getdataa to download all the data on the storage medium. When you are finished downloading the data, stop capturing the text by the HyperTerminal. The data can be further processed with mprplotter, as schematically shown here.
  2. Enter clear to move the pointer indicating the end of data available for download with the getdata command to the end of the current data stack. This will, in effect, make the data recorded on the DOMS's storage medium invisible for the getdata command, i.e., cleared. The data is, however, still there and can be retrieved by the getdataa command. To really clear all the data, enter cleara.

Figures showing DOMS settings and data line output

Figure 1: Main DOMS settings, after you type enter in an active connection with the DOMS.

Figure 2: More DOMS settings, after you enter config.

Figure 3: DOMS settings, after you enter spec, showing also the spectrometer settings.

Figure 4: Example of output data lines, without the spectrometer active. Data columns are separated with a semicolon (;), with column 1 = date, column 2 = time, column 3 = mark in the profile, columns 4-7 = four analog input channels, collumn 8 = depth. If the spectrometer is also active, column 9 = ID number of the file on the spectrometer unit's storage medium where the current spectrum is stored, column 10 = spectrometer signal (light intensity) averaged in a specific spectral region (see Tables below).

DOMS settings and commands

The tables below list implemented DOMS settings and commands. Each command must end with ENTER (\r) and, if successful, will respond with OK\r\n.

Profile settings

Setting Meaning Usage
pausereadX Pause (in seconds, X=0-99) between subsequent readings of the analog signals, including the spectral acquisition, if the spectrometer is active. pauseread1
markX Start mark in the profile. Mark (X=0-255) is increased by 1 everytime a step-size changes. mark1
readX Number of measurements at each depth, when measuring profiles (X=1-99). read5
boundaryaX In profiling, a boundary where the step-size changes from A to B (see stepY below) boundarya5000
boundarybX In profiling, a boundary where the step-size changes from B to C (see stepY below) boundaryb10000
posbX In profiling, a position where the motor waits after finishing the measurement of one profile (so-called waiting position). posb-2000
poscX In profiling, a position where the motor waits after finishing the measurement of the requested set of profiles (so-called stand-by position). posc-5000
stepaX Step size between the beginning of the profile (position 0) and the boundary A (see above). stepa1000
stepbX Step size between the the boundaries A and B (see above). stepb2000
stepcX Step size between the boundary B (see above) and the end position of the profile, where the end position is determined from repstepa (see below). stepc1000
repstepaX Total number of depths in the profile. One needs to do some simple calculation to find out the value of this setting to achieve the desired end depth of the profile.repstepa25
repstepbX Number of profiles in one set of profiles. repstepb10
repstepcX Number of sets of profiles. repstepc5
pauseaX Pause at each depth, before analog signals start to get recorded. pausea10
pausebX Pause between profiles. pauseb60
pausecX Pause between sets of profiles. pausec120
chanactXXXX Activate channels (X=1-4, more channels can be specified). If the channel is active, the signal in the channel can determine whether the measurement of the current profile should stop and the motor should move to the waiting position to start the next profile. This happens when the signal in the active channel exceeds the critical value specified in stopvalueY (see below).chanact13
stopvalueaX Specify the critical value in channel 0. stopvaluea200
stopvaluebX Specify the critical value in channel 1. stopvalueb100
stopvaluecX Specify the critical value in channel 2. stopvaluec20
stopvaluedX Specify the critical value in channel 3. stopvalued-200
statmodeX Specify what the system will be doing while stationary at the waiting position (posb) or the stand-by position (posc): Do nothing (X=0), log data while at position c (X=1), log data while at position b (X=2), log data while at both positions b and c (X=3) statmode3

Advanced settings

Setting Meaning Usage
progX Program number containing the active set of settings. Up to 10 (X=0-9) different sets of settings can be defined and stored under different program numbers. prog3
config manualmodeX Step size for the manual motor movement. config manualmode10000
config extX Activate external devices connected to the MPI-bus. The active status of each device on the MPI-bus is specified by the binary value of the bit associated with the device (0, 1, …, 7), with 1 = device activate, 0 = device inactivate. To activate devices associated with bits 0-7, set X to the decimal representation of the byte that you obtain if you sort the bits like this: [B7, B6, …, B1, B0]. For example, the spectrometer's active status is set by bit 4. To activate it, use X=16, because 16 = 00010000. Set X=0 to inactivate all external devices. config ext16
config setclock Set DOMS's clock. config setclock15:45 25.04.09

Spectrometer settings

Setting Meaning Usage
spec Show settings of the spectrometer, if active (see config extX below how to activate the spectrometer). spec
spec inttimeX Integration time in milliseconds. spec inttime30
spec sumbeginX Start band of spectrum integration. spec sumbegin30
spec sumendX End band of spectrum integration. The acquired spectrum is averaged from the start to the end band and the value is send as channel 5. spec sumend30

Motor movement commands

Command Meaning
setz0 Set the motor position to 0.
movez0 Move the motor to 0.
move Move motor by a step, specified by manualmode (see advanced settings).

Data handling commands

getdata Retrieve last logged data. See above.
getdataa Retrieve all data. See above.
clear Clear last logged data. See above.
cleara Clear all data. See above.

Data acquisition commands

run Start data logging. Data will be recorded every pauseread second.
auto Start automated profiling.
stop Stop the current DOMS activity (logging or profiling).

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doms/doms2pc_text.txt · Last modified: 2013/09/10 11:46 by lpolerec

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