AM16/32B without lid, glam view AM16/32B without lid, front angle view AM16/32B without lid, front view
AM16/32B without lid, glam view AM16/32B without lid, front angle view AM16/32B without lid, front view

AM16/32B 16-channel or 32-channel Relay Multiplexer

The AM16/32B multiplexer significantly increases the number of sensors that you can measure with a Campbell Scientific data logger. It interfaces with the data logger and adds terminals so that you can wire additional sensors of almost any type.
Environment | Communications | Campbell Scientific
  • Significantly increases the number of sensors the data logger can measure
  • Can multiplex 16, 32, or 48 sensors
  • Supports many types of sensors including thermistors, potentiometers, strain gages, vibrating wires, reflectometers, and soil moisture blocks
  • Decreases the cost of cabling individual sensors on long wire runs
  • Allows a relay address to be used to go directly to a specific channel—reducing power consumption and wear on the relay switches
  • Electrical surge protection via gas tubes on all analog I/O, and varistors or TVS diodes on all other connections
  • Prevents sensor-cable damage by providing strain relief for sensor leads and independent routing for sensor shield lines
  • Eliminates the requirement for dc blocking capacitors for gypsum soil moisture blocks, significantly reducing sensor cost
-NOTE- The protection on the reset, clock, and +12 V inputs are provided by 18 V TVS diodes.
Power Unregulated 9.6 to 16 Vdc
Scan Advance Occurs on the leading edge of the clock pulse transition (from below 1.5 V to above 3.3 V)
Minimum Clock Pulse Width 1 ms
Maximum Actuation Time for Relay 20 ms
Relay Operation Break before make
Initial Relay Resistance, Closed 0.1 ohm
Maximum Switching Current 500 mA (Switching currents greater than 30 mA [occasional 50 mA current is acceptable] will degrade the contact surfaces of the mechanical relays and increase their resistance.This will adversely affect the suitability of these relays to multiplex low voltage signals.Although a relay used in this manner no longer qualifies for low voltage measurement, it continues to be useful for switching currents in excess of 30 mA.)
Maximum Switching Voltage 50 Vdc
A voltage divider such as the VDIV10:1 may be needed between the AM16/32B and the data logger to stay within the input limits of the data logger channel.
Minimum Contact Life 5 x 107 operations
Maximum Contact Voltage Rating 70 V
Maximum Voltage 8 Vdc (clock level)
CE Compliance
  • EN 61326:1998
  • EN 55022:1998 Class B
Surge Complies with IEC61000-4-5, test level 3 (±2 kV, 2 ohm coupling impedance)
Operating Temperature Range
  • -25° to +50°C (standard)
  • -55° to +85°C (extended)
Dimensions 23.9 x 10.2 x 4.6 cm (9.4 x 4.0 x 1.8 in.)
Weight ~680 g (~1.5 lb)