Difference between revisions of "POT4"
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* Absolute maximum supply voltage is +-15V | * Absolute maximum supply voltage is +-15V | ||
* Supply current (DC input, no load) < 50mA (35mA typical) | * Supply current (DC input, no load) < 50mA (35mA typical) | ||
+ | * Due to the outputs driving 1uF capacitive loads, there is an additional AC supply current | ||
* Position output load current : I = (1uF) * 2*pi*f*Vo*sqrt(2)/2 or 4.4e-6 * f * Vo - thus a 100Hz 10V sine wave adds 4.4mA to the position output | * Position output load current : I = (1uF) * 2*pi*f*Vo*sqrt(2)/2 or 4.4e-6 * f * Vo - thus a 100Hz 10V sine wave adds 4.4mA to the position output | ||
− | * Differential output load current : | + | * Differential output load current : Vout = ~1e-6 * dVi/dT so I = (1e-6)*(2*pi*Vo)^2 * 1e-3 * sqrt(2)/2 or 2.8e-8 * (f*Vo)^2 |
+ | * a 50Hz, 10 Hz input has 2.2mA load from the position output, and 7mA on the velocity output | ||
+ | |||
+ | * a 100Hz, 10 Hz input has 4.4mA load from the position output, and 28mA on the velocity output | ||
== Identification == | == Identification == |
Revision as of 05:26, 9 March 2006
Contents
Power Supply
- +12V, GND, -12V required.
- Absolute maximum supply voltage is +-15V
- Supply current (DC input, no load) < 50mA (35mA typical)
- Due to the outputs driving 1uF capacitive loads, there is an additional AC supply current
- Position output load current : I = (1uF) * 2*pi*f*Vo*sqrt(2)/2 or 4.4e-6 * f * Vo - thus a 100Hz 10V sine wave adds 4.4mA to the position output
- Differential output load current : Vout = ~1e-6 * dVi/dT so I = (1e-6)*(2*pi*Vo)^2 * 1e-3 * sqrt(2)/2 or 2.8e-8 * (f*Vo)^2
- a 50Hz, 10 Hz input has 2.2mA load from the position output, and 7mA on the velocity output
- a 100Hz, 10 Hz input has 4.4mA load from the position output, and 28mA on the velocity output
Identification
- POT4 is a green PCB with white silk screen.
- Dimensions 1.75" x 0.85"
- Two mounting holes (diameter = 0.125"), top side clearance > 0.25"
- The color of DL1,DL2 indicates the input configuration of the board
Led Indicators
- (DL1, DL2) : A pair of single LEDs indicate the present of power. These LEDs are aligned with the power input to the boards.
- RED : configured for potentiometer inputs (#1-2)
- GREEN : configured with bridge inputs (#3-8)
- DK1 : The intensity of this dual RED/GREEN LED indicates the voltage of the "position signal".
Jumpers
- JF1 : 3 way jumper used to select source that drives that "Position" output. The signal source may be one of the following:
- Instrumentation amplifier output
- 2nd order low pass filter output
- 4th order low pass filter output
- JC1 : selects the "Shield" header signal source and is specified at assembly time. Signal sources include "GND", "COM", or "REF-".
Assembly Variations
POT4 can be built for either potentiometer input or bridge input. There are also several optional circuit modules.
- Detailed POT4 Gain by serial #
- boards #1, #2 : fully built with lowpass filters, differentiation and configured for potentiometer input. These boards use the LT1167 with gain G=1+49.4K/RA1.
- boards #3, #4 : minimally built for strain gauge bridge input. These boards use the INA122 with gain G=5+200K/RA1. Opamp LM324, 100K trim pot
- boards #5 - #8: built for strain gauge bridge input and are minimally built with 2nd order LP filter. These boards use the INA128 with gain G=1+50K/RA1. Opamp LM324, "503" trim pot
- board #9 : same as #1,#2 with INA128, Gain 1+50K/RA1 - populated for POT board
- 8-1-05 : board #9 returned for repairs.
Design Files
- Media:Pot4-sch-rev0-031505.pdf
- Media:Rpot4-pcb-top-rev0-031505.pdf
- Media:Rpot4-pcb-bot-rev0-031505.pdf
- Media:Pot4-for-strain-gauge-boards-5to8.pdf
FAQ
- Q: How to adjust the gain?
- Q: What is pinout of the headers?
- Q: What are the characteristics of the voltage reference?