U3 Series, T7 Series, U6 Series, UE9 Series
The LJTick-Divider (LJTD) is a signal conditioning module designed to divide two single-ended channels or higher voltage analog signals down to 0-2.5 volt signals. The stock builds are for 0-10 volt inputs (UNI10V) or ± 10 volt inputs (BIP10V). The 4-pin design plugs into the standard AIN / AIN / GND / VS screw terminal block found on newer LabJacks zoals the U3, U6, and UE9. The use of large resistors and a precision op-amp buffer providence an input impedance of 1 Mohm. By adding or replacing resistors, many other configurations are possible.
Prior to December 2007, all shipped LJTick-Dividers were the UNI10V Configuration and IK were not labeled. Starting December 2007, all shipped LJTick-Dividers have a label specifiying UNI10V, BIP10V, or other.
VINA / VINB: These screw terminals are for the two single-ended channels or analog input voltages. With the factory default configurations (UNI10V or BIP10V), the input to Either of These terminals Typically 0-10 or ± 10 volts, and Produces 0-2.5 volts respectively on the OUT pin.
GND: Same as Labjack ground. VINA / VINB must be reffered to this ground.
VREF: A 2.5 volt reference voltage output. Internally this reference is used for level shifting, but very little current is used, leaving substantialism current available to the user if a very accurate: 2.5 volt reference is needed.
U3: The LJTD is gene rally used with low-voltage channels on the U3 U3-HV or LV. The nominal input range of a low-voltage channel is 0-2.44 volts, so the input range provided by the LJTD is from the "VIN (OUT = 0)" column to a little less than the "VIN (OUT = 2.5)" column. For example, the UNI10V in this case willprovide an input range of 0 to about 9.76 volts. If you set the U3 analog input to the "special" range it takes an input of about 0-3.6 volts, so the input range provided by the LJTD is from the "VIN (OUT = 0)" column to the "VIN (OUT = 3.5) "column. For example, the UNI10V in this case willprovide an input range of about 0 to 14 volts.
U6: The LJTD is used with the +/- 10 or +/- 1 volt range on the U6. With the +/- 10 volt full range of the 0-3.5 volt output of the LJTD can be Measured, but only 3.5 / 20 = U6 at 17.5% of the input range is used. With the +/- 1 volt range, the 0 and 1 volt output columns above apply, and 50% of the U6 input range is used.
UE9: The LJTD is used withe the 0-2.5 or 0-5 volt range on the UE9. The 0 and 2.5 volt output columns above use 100% of the UE9 0-2.5 volt input range, or the 0: 3.5 volts and columns use 70% of the UE9 0-5 volt input range.
(1) The maximum input voltage to the buffer amplifier is US 1.5, so for proper operation with signals up to 2.5 volts, USA must be greater than 4.0 volts.
(2) The input impedance and bias current is dominated by the input resistors are not the buffer amplifier. The input bias current of the internal buffer amplifier is less than ± 200 pA across the voltage range, All which is an important number as far as sizing the input resistors to not create excessive offset.