Campbell Scientific AM25T 25-Channel Solid State Multiplexer - Manual (Page 7)

AM25T Solid State Multiplexer
The terminal strips that run the length of the AM25T are for sensor
connections. All inputs are protected by spark gaps. All terminals accept
stripped and tinned lead wires up to 1.5 mm (0.059 inches) in diameter. A
strain-relief flange is located between the input terminals.
CLK RES EX AG 1H 2H 2L 3H 3L 4H 4L 5H 5L 6H 6L 7H 7L 8H 8L 9H 9L 10H 10L 11H 11L
15H 15L 16H 16L 17H 17L 18H 18L 19H 19L 20H 20L 21H 21L 22H 22L 23H 23L 24H 24L 25H 25L 14H 14L 13H 13L
1L +12 HI LO
12H 12L
AM25T AM25T SOLID STATE THERMOCOUPLE
MULTIPLEXER SOLID STATE THERMOCOUPLE
MULTIPLEXER
MADE IN USA
S / N
MADE IN USA
S / N
MADE IN USA
AM25T AM25T SOLID STATE THERMOCOUPLE
MULTIPLEXER SOLID STATE THERMOCOUPLE
MULTIPLEXER
LOGAN UTAH
1011
Logan, Utah Logan, Utah
FIGURE 1. AM25T Thermocouple Multiplexer
1.3 Operation
The AM25T is connected to the datalogger with eight insulated wires and a
large ground wire. These wires are used to power and control the multiplexer,
and connect the common analog inputs to the datalogger.
Measurement Terminals
There are 25 differential channels on the AM25T. These channels are labeled
1H and 1L through 25H and 25L. The channels are sequentially connected and
reversed to the common channels HI and LO.
Excitation Terminal
This terminal is used to excite the reference temperature (RTD) on the
AM25T. The excitation line is protected from transients with a transorb.
(Earlier versions of the AM25T, prior to 1839, used a zener diode for
protection. The diode limited the negative excitation voltage to -400 mV).
Power (12 V)
The AM25T requires a 9.6 to 16 VDC (12 VDC nominal) power supply.
In low current drain applications, it is convenient to power the AM25T from
the datalogger's battery. For power intensive operations, use a high Amp hour
12 VDC battery.
See Campbell Scientific’s application note on power supplies for information
on calculating the power requirements of your system.
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