Hewlett Packard 3852A
Data Acquisition/Control System, Refurbished

• Eight Function Module Slots
• Data Acquisition Operating System
• System Timer
• Measurement Pacer
• Full Alphanumeric Keyboard, Command and Result Displays

• Multitasking operating system prioritizes and timeslices tasks
• Powerful 3852A command statements simplify complex measurements.
• Execution speed of command sequences are enhanced by executing subroutines stored in the 3852A memory.
• Built-in, easy-to-use transducer conversions are supported for thermocouples, thermistors, RTDs, and strain gages.
• Post-processing and data reduction before transferring results to a computer are achievable by first storing data to the 3852A internal memory.
• Limit checking of analog measurements is performed in real time or after the measurements have been stored in mainframe memory.

• Real-time interrupts allow higher priority tasks and external inputs to be serviced at any time
• Asynchronous communication with a computer is achieved through input and output buffering.
• Control can be timed using built-in clock and alarm capabilities (can cause an interrupt).
• A built-in pacer simplifies measurement timing and triggering.
• Multiple voltmeters can be used.  The high-speed voltmeter can control scanning, timing, and triggering of its own high-speed FET multiplexer subsystem via ribbon cable.  Several of these subsystems can run simultaneously.

• Thermocouples
• Thermistors
• Platinum RTDs
• Strain Gages

• Up to seven extenders may be used with each 3852A mainframe.
• Any slot can be used for any function module and multiple voltmeters can be used with parallel triggering.
• All mainframe functions, including interrupts and triggering, are available through the extender control cable.

• DC Voltage
• Resistance
• AC Voltage

Benefits

• Integrating A/D rejects normal mode noise at multiples of the power line frequency.
• Guarded input maximizes common-mode rejection.

• Integration selection (number of power line cycles) is key to optimizing these performance parameters.
• This voltmeter provides the fastest DC reading rates available with power line-related noise rejection.

• Use two-wire ohms for measurements where lead resistance not critical.
• Use four-wire ohms where inaccuracies due to measurement leads cannot be tolerated (most accurate measurement technique for RTDs).
• Use offset-compensated ohms to correctly measure resistance in the presence of series voltages (often caused by thermocouple effects).

• DC Voltage
• DC Resistance

• A measurement rate of 100,000 readings/sec with auto-ranging is achieved by directly controlling up to six (eight in an extender) High-Speed FET Multiplexers through a dedicated ribbon cable.
• Multiple High-Speed Voltmeters can be triggered simultaneously and operate independently.

• On-board buffer is included for over 8,000 readings (44702B) that can be transferred to mainframe internal memory or to hard disc via GPIO and a DMA controller while taking measurements. 
• Dedicated triggering is achieved with on-board pacers.
• Balanced input, equal impedance between high-to-chassis and low-to-chassis, gives good common mode noise rejection.

• Voltage
• Resistance
• Thermocouples
• Strain Gages

• Relay multiplexers minimize errors due to thermal DC offsets, crosstalk, and injected (bias) currents.
• The relay multiplexers have high, low, and guard terminals to maximize common mode noise rejection.
• A single-ended multiplexer (44706A) lowers your cost per channel.
• With shunt and series jumpers in each channel of the 44705A/H and 44708A/H multiplexers, you can easily install a one-pole low-pass filter for additional noise rejection, a voltage divider to extend relay lifetime, or a shunt resistor to measure current.
• Differential or common mode voltages up to 350 V peak or 250 Vdc can be handled by the 44705H and 44708H modules.
• Scanning is break-before-make to prevent inadvertent connections of circuits being measured.
• Each lead to the back-plane and common terminals has a 100Ω  resistor in series to prolong the lifetime of the relay contacts.  Due to placement, these resistors contribute no error when measuring 2-wire ohms resistance using the 44701A Integrating Voltmeter.  The resistor can be shorted, but this can seriously shorten relay contact life if relatively high voltages or currents are switched.
• Tree switch relays automatically isolate each bank of relays from the back-plane to reduce crosstalk and improve settling time.

• Theromcouple types can be mixed on the 44798A/H multiplexer to optimize accuracy over the temperature ranges needed.
• Thermocouple compensation is handled automatically with no extra wiring.

• Strain sensitivity can be optimized using finger-moveable jumpers to select between 1/4-, 1/2-, and full-bridge configurations.  The 44717A and 44718A multiplexers each support 10 bridges for 120Ω  and 350W strain gages.
• No manual adjustments are required to balance the bridge.
• Strain accuracy is independent of long-term bridge excitation voltage changes because the excitation voltage is automatically measured and included in the strain calculations.
• The excitation voltage is always applied, never switched, reducing errors due to dynamic heating and cooling of the gages.
• Connection to an available Wagner ground reduces errors due to gage leakage current.

• Voltage
• Resistance
• Thermocouples
• Strain Gages

• A throughput rate of 100,000 readings/sec is realized using High-Speed FET Multiplexers (44711A/44712A/44713A) directly controlled through a dedicated ribbon cable by the 13-bit High-Speed Voltmeter.
• Up to six (eight in an extender) High-Speed FET Multiplexers can be controlled through this ribbon cable.
• The 24-channel multiplexers switch high and low only.  Each floating input is balanced (that is, equal impedance between high-to-chassis and low-to-chassis) to provide good common mode noise rejection.
• For lower costs per channel, single-ended multiplexing of 48 channels ( 44712A) is also available (has no common mode noise rejection, however).

• FETs have no mechanical limitations (no wear out due to switching).
• Similar to their relay counterparts, the 44709A/44710A/44719AA/44720A FET multiplexers have high, low, and guard connections for better common mode rejection than the high-speed FET multiplexers.

• Transient DC voltages
• Dynamic strain gages
  The Track/Hold Multiplexers have powerful capabilities for applications in acoustic analysis, environmental tests and the testing of engines, electromechanical products, mechanical products, rubber belts, elevators, hydraulics, motors, pressure transducers and materials. 
• Dynamic strain applications include seismology/ground characterization, machine control and characterization, and physical tests of engines, aircraft, mechanical products, hydraulics and motors.  Tests using strain gages include operating and burst tests, as well as the simultaneous detection of "glitches."

• Enhance dynamic signal measurement accuracy by measuring a number of channels simultaneously via internal or external strobes.
• Set gains of 1, 10, or 100 on each channel, minimizing computation time to obtain higher reading rates.
• Reduces settling errors when switching between low-level and high-level signals.
• Use the analog peak detect/hold feature to capture either positive or negative peaks without having to sample at a high rate of speed.
• Boost system throughput in some applications by reducing the requirements to over-sample.  Using the ribbon cable, it connects to the 44702 high speed voltmeter for high speed operations.
• Measure dynamic strain accurately:
  Utilize on-board excitation that is provided separately for each bridge.
  Select quarter, half, or full-bridge configurations.
  Eliminate offsets with electronic nulling.

• Arbitrary Waveforms
• DC Voltages
  This 2-channel no-isolated module provides arbitrary waveforms and stimulus signals for product test and characterization applications.  Applications include the testing of satellites, engines, electromechanical products, aircraft, automobiles, mechanical products, materials, chemicals, and elevators.

• Provides a stimulus voltage signal with a step rate of up to 800 kHz.
  Outputs a DC voltage or any arbitrary waveform stores in its own memory.
  Output waveforms, once initiated, can run continuously regardless of the activities being performed  by the 3852A mainframe.
  Channels have independent timebases that can be synchronized with each other or with external events.  External timebases can also be used.
  Waveforms can be single-shot (one cycle of the waveform) or continuous.  Channel 0 can also perform n repetitions of the waveform (n = 1 to 65,536).
  Sine, triangle and square (50% duty cycle) waveforms can be calculated and loaded from the 3852A with one command. 
• Random access memory is available for each channel on this accessory.
  Each channel has enough memory for 32,400 waveform points in which each point is defined as both a voltage level and length of time at that level.  As a result, memory is used efficiently.
  Up to 64 different waveforms on each channel can be stored in memory.
  Arbitrary waveforms can be loaded from a user-defined array or a real array or high-speed voltmeter readings.

• DC Voltage
• DC Current

• Four channels are provided on each module.
• Each channel can be configured using finger-moveable jumpers to output either unipolar or bipolar voltage, or unipolar current.  Reconfiguration may require recalibration of the changed channel.  Recalibration consists of adjustments to zero offset and gain potentiometers, and can be performed with the 44701A Integrating Voltmeter or equivalent.  Three configurations (4-Channel Voltage - 44727A; 4-Channel Current - 44727B; 2-Channel Voltage, 2-Channel Current - 44727C) are available to make reconfiguration unnecessary in most cases.
  Channels are isolated and can be connected in parallel for current or in series for voltage to expand the useable ranges.
  Each channel configured for voltage has remote sense capabilities to ensure accurate voltages at the device.

• Stepper Motor Control Signals
• Limit Inputs
• Built-in Quadrature Counters
• Pulse Output

• Output a continuous stream or a fixed number of pulses.
• Program separate acceleration and deceleration rates for trapezoidal motion profiles.
• Halt output pulses when limits are reached or from the emergency stop input.
• Built-in quatrature counter on each channel gives position feedback.

• Output a set number of pulses or a continuous stream.
• Set, accelerate, and decelerate both pulse width and pulse rate.

• Count Measurements
• Period Measurements
• Frequency Measurements
• Interrupts

• The counter/totalizer accurately measures logic or RMS inputs with frequencies up to 200 kHz.
• By multiplexing between five isolate channels and five non-isolated channels, a total of ten connected channels is possible (only five can operate simultaneously).
• Each DC logic channel independently counts on either positive or negative signal transitions.  Non-isolated, low-level RMS inputs are measured using a zero-crossing detector.
• Any channel that is totalizing can be programmed to set an interrupt for a counter roll-over to zero.
• For isolated DC inputs, nominal voltages are separately selected for each channel by finger-moveable jumpers.  For non-isolated inputs, either TTL or low-level RMS inputs are also separately selected for each channel by finger-movable jumpers.
• Debounce times (common to all channels) can be programmed to prevent false counts.
• With shunt and series jumpers in each channel, you can easily install a one-pole low-pass filter for rejection of unwanted signals.

• Logic Readings
• Totalize Count Measurements
• Interrupts

• Isolated inputs detect the presence of DC (44721A 16-channel digital input) or AC (44722A 8-channel digital input) inputs based on nominal voltages selected by finger-movable jumpers.
• Each channel can independently totalize positive or negative (whichever is selected) logic transitions.
• Voltage selection and function can be set independently on each channel.
• Any channel can be programmed to set an interrupt for an edge occurrence (positive or negative) or a counter roll-over to zero.
• Debounce circuitry that is common to all channels prevents erroneous readings on inputs that are still changing after a logic level transition.
• For detecting whether switches are opened or closed, the 44721A has a non-isolated five volt supply at the terminal module with 9.4 kW ± 10% pull-up resistors on each input.

• High-speed Digital Input and Output
• Triggered Input and Output
• Interrupts
• Output Handshaking

• Input 16 channels or output 16 channels over 150,000 times per second.
• Capture and load 16-bit patterns with external triggers.
• Interrupt on any input channel on any transition or on a user-specified 16-bit pattern.

• Open Drain Digital Outputs

• Open drain outputs are used to control DC devices with up to 55 V, or drive TTL logic levels.  An external power supply and external pull-up resistors are required.

• Voltage
• Current
• Power

• Both the 44725A and 44728A use single-pole double-throw (SPDT) Form-C relays that return to their normally closed positions at power down.  The 44725A 16-channel general purpose relays are for switching low-level power or moderate voltages and currents in an experiment while minimizing errors due to cross talk and thermal DC offsets.  More DC or AC power can be switched with the 44728A 8-channel relay actuator.
• The 44729A 8-channel AC power controller distributes AC power.  It switches "on" at the zero voltage crossing and "off" at the zero current crossing for long device life and low transient generation.  Each channel has a relay and solid state switch in parallel to provide an exceptional combination of switch life and low on-resistance.

• HP-IB disc drives (CS80/SS80)
• HP-IB printers
• HP-IB instruments

• Remote operations without a computer.
• At power-up, load subroutines into a 3852A from an HP-IB disc drive and start executing them.
• Send data to an HP-IB disc drive without using a computer.
• Print out data stored in the 3582A without using a computer.
• Control other HP-IB instruments directly with 3582A.