GP-10 and GP-10S
Patch Panel Description
operational amplifiers . . . Eight high gain, single ended, inverting amplifiers are brought out to the panel for traditional analog computer patch cord programming. (The non-inverting base connected to ground creates the single ended configuration. The inverting base then typically becomes the summing junction.) GP-10S amplifiers feature high gain, high input/low output impedance, low temperature drift, sufficient output current to drive general purpose program loads, 6 db/octave roll-off characteristics to assure stable, repeatable operation under widely varying resistive/capacitive input and feedback impedances.
Color coding: red, amplifier outputs; gray, summing junctions.
summer/integrators . . . Amplifiers 1 thru 4 each have an internal FET electronic switch network that creates SJ and SJ' summing junctions, switched summing junction paths required for an integrator's two primary modes: initial condition and operate. (Logic patched to the SW jacks control the switches.) An amplifier is programed as a summer/integrator by patching a capacitor as the feedback. The output voltage equals the inverted integral of the sum of the input currents (plus/minus the initial condition) where the integration rate is the reciprocal of the R*C time constant. (Analog computer programming assumes a "1" resistor and "B" capacitor to produce a nominal one second. Actual time constants are determined by the actual resistor and capacitor values.)
Switch logic: Ground or a positive voltage applied to the SW jack places the switch into the initial condition (SJ' conducting, SJ shut off) state. A negative 3.5 volts or less places the switch into the operate (SJ conducting, SJ' shut off) state. A negative 2 thru 3 volts places the switch into a "hold mode," HD, state where the summing resistor network is electronically disconnected and the capacitor holds its charge until placed back into either IC or OP.
Color coding: red, amplifier outputs; green, resistor and IC inputs; gray, summing junctions; white, control logic.
summer amplifiers . . . All patch panel amplifiers (1 thru 8) may be programed as summers by patching a resistor feedback. (Regarding the above discussed amplifiers 1 thru 4, absence of SW control patching latches the SW logic into the SJ conducting, SJ' shut off, state, a configuration identical to the other amplifiers. Amplifiers 1 thru 4 offer the feature of using the IC network by patching SJ to SJ' so that the initial condition resistor becomes a "1" resistor feedback and the IC input an addition "1" resistor input.)
Resistors may also be externally connected. Comdyna offers special module-plugs to add inputs or special non-standard resistor values.
Color coding: red, amplifier outputs; green, resistor and IC inputs; gray, summing junctions.
coefficient potentiometers . . . Coefficient potentiometers are configured as attenuators (bottom ends grounded) to be used primarily for entering parameters (constants) into a program. As an attenuator, an input (top jacks) is multiplied by its "setting," (an adjustment between 0 and 1.0,) where the wiper is the output. A coefficient is set by depressing the adjacent button which replaces the top patched input with +10v so that the wiper voltage indicates the top to total resistance ratio which is the setting.
Color coding: yellow, inputs and wipers.
initial condition potentiometers . . . Initial condition potentiometers, like coefficient potentiometers, are configured as attenuators but are used only to enter summer/integrators 1 thru 4 initial conditions. The adjacent toggle switch enables initial conditions to be both negative and positive or, in the center-off position, zero.
Color coding: yellow, inputs and wipers.
multiplier/dividers . . . Four multiplier networks may be programed for multiplication and/or division of two analog variables. Multiplication (X * Y) occurs when the network is patched to an amplifier summing junction and the feedback is a resistor. Division (U / X) occurs when the network is patched to the summing junction, the Y input is patched as the feedback, the denominator is patched to the X input and the numerator U to an input resistor.
Color coding: brown, inputs; gray, network summing junction.
Color coding: red, plus 10 volts; yellow, minus 10 volts.
Requirements for use:
Rear Connector . . . 25 pin, type D Sub-connector. A female connector terminates inputs, amplifier outputs and control logic to mate with a male connector/cable to be supplied by the user.
Digital Voltmeter . . . An external digital voltmeter is required to set the coefficient potentiometers and display static amplifier output values.
Mode Control . . . An external mechanical or electronic switch is required to control system integrator modes.
Time Scale Relay . . .An external mechanical or electronic switch is required to activate integrator time scale relays (if provided.)
Shown below with the front panel hinged opened, the GP-10S mounts into a standard, 19"rack.
All the electronic assemblies and component are accessible behind the panel.