Specifications

AM25T Solid State Multiplexer

Example 3. 21X Program for Measuring 25 Type T Thermocouples or Voltage Sensors Using

a Differential Instruction

*Table 1 Program

01: 10 Execution Interval (seconds)

01: Do (P86) ;Turn On AM25T

1: 42 Set Port 2 High

02: Full Bridge (P6) ;Measure the output of the reference temp. full bridge

1: 1 Reps

2: 3 50 mV Slow Range ;See Table 6-1 for older AM25T multiplexers

3: 1DIFF Channel

4: 1 Excite all reps w/Exchan 1

5: 2400 mV Excitation ;See Table 6-1 for older AM25T multiplexers

6: 1 Loc [ RefTemp_C ]

7: -0.001 Mult

8: 0.09707 Offset

03: BR Transform Rf[X/(1-X)] (P59) ;Calculate RTD resistance R/R0

1: 1 Reps

2: 1 Loc [ RefTemp_C ]

3: 10.025 Multiplier (Rf)

04: Temperature RTD (P16) ;Calculate reference temperature

1: 1 Reps

2: 1 R/R0 Loc [ RefTemp_C ]

3: 1 Loc [ RefTemp_C ]

4: 1 Mult

5: 0 Offset

05: Beginning of Loop (P87) ;Loop through thermocouple channels

1: 0 Delay

2: 25 Loop Count

06: Do (P86) ;Clock the AM25T twice

1: 41 Set Port 1 High ;Setting high then low is faster than pulsing w/21X

07: Do (P86)

1: 51 Set Port 1 Low

08: Do (P86)

1: 41 Set Port 1 High

09: Do (P86)

1: 51 Set Port 1 Low