Simplifying cryogenic temperature sensor excitation

Cryogenic temperature monitoring requires a constant balance between supplying enough power to make good measurements and keeping the power low enough to minimize sensor self-heating errors. Lake Shore’s 240 Series optimize measurement accuracy and resolution by automatically adjusting excitation level based on the temperature and connected sensor.

Thermal EMF offsets are also eliminated using current reversal techniques, canceling out these unwanted measurement errors that would be present in any other equipment not specifically designed for cryogenic measurements.

Normal mode

Best option for most installations. Provides the most accurate and precise measurements and is available on all 240 Series models.

  • Current reversal available to remove thermal EMF offsets
  • Modified measurement window to ignore signal rise when using long cable runs
  • Fixed 100 ms update rate for the Model 240-2P or 400 ms for the Model 240-8P

normal mode

High-speed mode (240-2P only)

Measurement option for times when low latency measurements are required. This feature is best used with sensors with extremely fast thermal response times.

  • Update rates from 1 to 100 ms; configurable to match the network update rate
  • Constant measurement with no interruptions caused by current reversal of input switching
  • Current reversal not available in this mode, so thermal EMF offsets should be anticipated and managed

high speed mode

240 overview

native fieldbus integration

240 more

built-in temperature conversion