Spectrum Brands MI.20xx - Manual (Page 44)

44 MI.20xx Manual
Setting up the inputs Analog Inputs
Input termination
All inputs of Spectrum’s analog boards can be terminated separately with 50 Ohm by software programming. If you do so, please make sure
that your signal source is able to deliver the higher output currents. If no termination is used, the inputs have an impedance of 1 Megaohm.
The following table shows the corresponding register to set the input termination.
Automatical adjustment of the offset settings
All of the channels are calibrated in factory before the board is shipped. These settings are stored in the on-board EEProm under the default
settings. If you have asymmetrical signals, you can adjust the offset easily with the corresponding registers of the inputs as shown before.
To start the automatic offset adjustment, simply write the register, mentioned in the following table. Because the adjustment of all the channels
in all different input ranges can take up some time, it can be useful to adjust only the current input range to safe time.
Before you start an automatic offset adjustment make sure, that no signal is connected to any input. Leave
all the input connectors open and then start the adjustment. If you adjust all ranges, this can take up some
time. All the internal settings of the driver are changed, while the automatic offset compensation is in
progress.
As all settings are temporarily stored in the driver, the automatically adjustment will only affect these values. After exiting your program, all
adjustments will be lost. In some applications it can be nevertheless necessary to adjust the boards offset settings permanently. To give you
a possibility to save your own settings, every Spectrum board has at minimum one set of user settings that can be saved within the on-board
EEPROM. The default settings of the offset and gain values are read-only and cannot be written to the EEProm by the user.
You can easily either save adjustment settings to the EEPROM with SPC_ADJ_SAVE or recall them with SPC_ADJ_LOAD. These two registers
are shown in the table below. The values for these EEPROM access registers are the sets that can be stored within the EEPROM. The amount
of sets available for storing user offset settings depends on the type of board you use. The table below shows all the EEPROM sets, that are
available for your board.
If you want to make an offset adjustment on all the channels and store the data to the ADJ_USER0 set of the EEPROM you can do this the
way, the following example shows.
To work with these settings instead with the default ones at for example another day, you need to restore your user settings with the help pf
the SPC_ADJ_LOAD register as the following example shows.
Register Value Direction Description
SPC_50OHM0 30030 r/w A „1“ sets the 50 ohm termination for channel0. A „0“ sets the termination to1 MOhm.
SPC_50OHM1 30130 r/w A „1“ sets the 50 ohm termination for channel1. A „0“ sets the termination to1 MOhm.
SPC_50OHM2 30230 r/w A „1“ sets the 50 ohm termination for channel2. A „0“ sets the termination to1 MOhm.
SPC_50OHM3 30330 r/w A „1“ sets the 50 ohm termination for channel3. A „0“ sets the termination to1 MOhm.
Register Value Direction Description
SPC_ADJ_AUTOADJ 50020 w Performs the automatic offset compensation in the driver either for all input ranges or only the actual.
ADJ_ALL 0 Automatic offset adjustment for all input ranges.
ADJ_CURRENT 1 Automatic offset adjustment only for the current chosen input range.
Register Value Direction Description
SPC_ADJ_LOAD 50000 w Loads the specified set of settings from the EEPROM. The default settings are automatically loaded,
when the driver is started.
r Reads out, what kind of settings have been loaded last.
SPC_ADJ_SAVE 50010 w Stores the actual settings to the specified set in the EEPROM. T
r Reads out, what kind of settings have been saved last.
ADJ_DEFAULT 0 Default settings can be loaded only. These settings cannot be saved by the user.
ADJ_USER0 1 User settings 0. This is a valid set for storing user offset settings to.
SpcSetParam (hDrv, SPC_ADJ_AUTOADJ, ADJ_ALL ); // Activate offset adjustment on all channels
SpcSetParam (hDrv, SPC_ADJ_SAVE , ADJ_USER0); // and store values to USER0 set in the EEPROM
SpcSetParam (hDrv, SPC_ADJ_LOAD , ADJ_USER0); // and load values to USER0 set in the EEPROM