1.1. Overview

The Lake Shore M81-SSM Synchronous Source Measure System is a modular system for applying voltage and current stimulus to experimental systems, as well as measuring voltages and currents produced by experimental systems.

This manual applies to 3 model numbers that support varying numbers of connected modules:

M81-SSM-2

M81-SSM Synchronous Source Measure System with 1 source channel and 1 measure channel

M81-SSM-4

M81-SSM Synchronous Source Measure System with 2 source channels and 2 measure channels

M81-SSM-6

M81-SSM Synchronous Source Measure System with 3 source channels and 3 measure channels

The MeasureReady™ M81-SSM provides a modular approach to multi-channel voltage/current sourcing and measuring of signals from DC to 100 kHz AC while also ensuring very tight timing synchronization between up to 6 total channels due to a unique synchronous sampling architecture called MeasureSync™ technology. This proprietary Lake Shore measurement architecture is a unique approach to ensuring that all source and measure signals remain inherently aligned in time with no user intervention required beyond selecting the desired signal types, amplitudes, frequencies and timing references for each source and measure channel in a given setup.

The compact instrument coordinates all source and measure channel updates to ensure precise timing alignment with the single main sampling system which forms the basis of the MeasureSync™ technology and architecture. In addition to the multi-channel timing synchronization benefits, MeasureSync™ technology also ensures consistent and near real time sampling performance across the M81-SSM’s full DC to 100 kHz signal bandwidth and across all connected source and measure amplifier modules. And it does so regardless of the distance between instrument and local/benchtop, rack or remotely mounted signal amplifier modules, which can be located up to 2 m away (10 m optional) from the instrument mainframe, further adding flexibility to each test setup while maintaining full specified timing synchronization and signal sourcing and measurement performance.

The ability to locate source and measure signal amplifiers as close as possible to apparatus, samples or devices under test minimizes signal level cabling length and the associated cabling leakage, noise and increased settling times, any of which can be limiting factors for ultra-low signal levels transport and voltage/current characterization applications.

The M81-SSM architecture and unique technologies provide the configuration flexibility of a modular system without the usual mechanical or performance limitations inherent in card cage or other mainframe centric form product yielding significant cost, time and performance advantages in low level electrical measurement applications.

1.2. Features

Unique real-time sampling architecture for synchronous sourcing and measuring

  • MeasureSync™ technology for simultaneous source module update and measure module sampling timing across all channels

  • DC/AC amplitude and phase detection is user-selectable on all measure channels

  • Common DAC/ADC sampling clock ensures highly precise and consistent source/measure timing coordination between 3 sources and 3 measures

Designed for scientific-grade low-level measurement applications

  • Linear module power supply architecture for lowest possible source/measure noise

  • Fully analog signal paths between data converters, modules, and the device under test (DUT)

  • Remote modules for the shortest possible signal path to the DUT, which separates sensitive analog circuits from digital circuits and unwanted sources of interference typical of traditional single-enclosure instrument designs

The absolute precision of DC plus the detection sensitivity performance of AC instrumentation

  • All source and measure channels are capable of DC and AC to 100 kHz signals

  • Optimized for fundamental, harmonic, and phase AC plus DC biased measurements

  • Modularity allows for flexible, user-configured modules to suit a specific application

Unique, flexible instrument/distributed module architecture

  • Remote-mountable amplifier modules are interchangeable between instruments

  • Modules are dynamically recognized when the system is reconfigured

  • Uses a clean, simple UI and a common programming API for fast setup and a shorter learning curve

1.3. Functions

The M81-SSM provides:

Up to 3 source channels capable of:

  • DC excitation

  • AC excitation up to 100 kHz

Up to 3 measure channels capable of:

  • DC measurement

  • AC measurement (RMS, Peak)

  • Lock-in amplifier measurement (X, Y, R, θ)

And additionally:

  • A reference input for acquiring external frequencies

  • A reference output to provide a phase reference to external equipment

  • A configurable analog output

  • 2 general purpose digital inputs

  • 2 general purpose digital outputs