Instruction manual
AM16/32 Relay Analog Multiplexer
29
21x
CR7
CR10(X)
G
COM EVEN H
COM EVEN L
EVEN H
EVEN L
SENSOR SHIELDS
COM
"4 X 16" Mode
LL
L
HH
H
LL
L
HH
H
COM ODD H
COM ODD L
CU
CO
CU
CO
ODD H
ODD L
CU
CO
CU
CO
CR23X/
CR5000
FIGURE 17. Differential Thermocouple Measurement with Reference Junction at the
Datalogger.
21x
CR7
CR10(X)
G
COM EVEN H
COM EVEN L
EVEN H
EVEN L
SENSOR SHIELDS
COM
"4 X 16" Mode
LL
L
HH
H
AG
HH
H
EE
E/VX
LL
L
HH
H
COM ODD H
COM ODD L
107
ODD H
ODD L
CU
CO
CU
CO
CU
CU
CU
CU
CR23X/
CR5000
FIGURE 18. Differential Thermocouple Measurement with Reference Junction at the AM16/32.
If a mix of TCs and other sensor types are multiplexed through the
AM16/32, it is generally best to locate the reference junction on the
AM16/32, as shown in Figure 18.
AM16/32 Reference - An external reference, usually a thermistor, can
be located at the AM16/32, as shown in Figure 18. This approach
requires an additional single-ended datalogger input to measure the
reference. Position the reference next to the COM terminals and,
when practical, measure the thermocouples on SETs that are in close
proximity to the COM terminals in order to minimize thermal
gradients.
Thermal Gradients - Thermal gradients between the AM16/32's sensor
input terminals and COM terminals can cause errors in thermocouple
readings. For example, with type T thermocouples, a one degree
gradient between the input terminals and the COM terminals will
CR23X/
21X CR1000/
CR7 CR10(X)
CR5000
CR23X/
21X CR1000/
CR7 CR10(X)
CR5000