1
AM25T Solid-State Thermocouple
Multiplexer
1. Introduction
The AM25T (FIGURE
) multiplexer increases the number of channels for
measuring thermocouples or voltage sensors with Campbell Scientific data
loggers. The AM25T is positioned between the sensors and the data logger.
The data logger controls the AM25T solid-state relays, sequentially connecting
each sensor to the data logger.
The AM25T is not suitable for resistive bridge measurements (high impedance
of the solid-state relays) or multiplexing power (25 mA maximum switching
current).
A maximum of 25 thermocouples (differential voltage measurement) can be
multiplexed by an AM25T. Single-ended voltage measurements are not
recommended.
The AM25T must be used in a noncondensing environment. An enclosure is
required for field use. In applications where one or two multiplexers are
deployed in the field, the ENC12/14 can be used. The ENC16/18 can be used
to house several multiplexers at the same site.
FIGURE 1-1. AM25T Solid-State Thermocouple Multiplexer