4220A/B Automated Low-Thermal Matrix Scanner

  • 20 Four-Terminal Channels
  • Sealed Relays with 4 A Carrying Current
  • 4-Conductor Wire or Binding Post Inputs
  • Optional 30 A Capacity
  • Low-Thermal Matrix Design
  • 1000 V DC
  • Insulation Resistance > 1012 Ω
  • Front Panel or IEEE-488 Interface
Features & Benefits

Measurements International’s series of Low-Thermal Scanners are ideal for automating precision measurements to sub-ppm accuracy. The model 4210, 4216 or 4220 series of low-thermal precision scanners are ideal for use in automated resistance and thermometry applications where several artifacts need to be calibrated efficiently and accurately. This series of Matrix Scanners improves the efficiency by eliminating the need to continually change leads when measuring groups of resistors.

The input channels can be manually selected from the front panel or via the standard IEEE-488 interface when used in an automated system. LEDs on the front panel enable the operator to quickly verify which channels have been selected.

Front panel LEDs designated A and B indicate the selected channels. Additionally, the A and B boards are separated to improve the insulation resistance. Protection from selecting the same relay on both sides is also available on the rear panel IEEE address switch.

The relay boards are thermally isolated to maintain equilibrium in the switching areas. Furthermore, the A and B boards are separated to improve the insulation resistance. Ultra-sensitive, high-efficiency, polarized sealed relay technology is used to eliminate self-heating in the relay. Sealed relays have the advantage that they avoid contamination build up commonly found in competitive scanners where contamination builds up between the relay contacts and the contacts on the printed circuit boards.

A choice of six scanners is available. 10-channel, 16-channel, and 20-channel with either tellurium copper binding posts or 2-metre four-conductor Teflon cables.

In the A-series of scanners, the copper terminals are mechanically connected to the copper pads on the relay boards to reduce the thermals normally generated by soldered connections, thus reducing switching errors.

The 4220A has 20 four-terminal tellurium copper binding posts and 2 outputs consisting of 8 tellurium copper binding posts. The model 4220B has 20 four-conductor Teflon cable inputs with 2 four-conductor Teflon cable outputs. The 4220A is also available in a 30 Amp model to handle currents up to 30 A (model 4220A/30).

Operation Four-Terminal Matrix
Thermal EMF’s < 50 nanovolts
Error Contribution < 20 nanovolts
Contact Configuration Relay – Two Coil Latching
Max Carrying/Switching Current 4/2 Amps @ < 30 Volt (DC)
Maximum Working/Switching Voltage 1000/220 Volts @ < 100 mA (DC)
Contact Resistance < 0.05 Ω
Expected Relay Life 10Operations
Insulation Resistance > 1012 Ω
4210A, 4216A and 4220A Connection Type Tellurium Copper Binding Posts
4220A Inputs (20 Channels) Rear Panel/
Outputs (Rear Panel)
4220B Inputs (20-Channels) Rear Panel/Outputs (Rear Panel) 20/2
Manual/IEEE-488 Both
Operating Environment 18 to 34 °C, 10 to 80 % RH
Warranty 1 Year Parts & Labour

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