Model 109B & 109 BAM Temperature Probe
The 60 and 50 Hz integration options include a 3 ms settling time; longer
settling times can be entered into the Settling Time parameter. The example
Therm109 instruction listed below has a 20 mSec (20000 µSec) delay:
‘Therm109 ( Dest, Reps, SEChan, ExChan, SettlingTime, Integ, Mult, Offset )
Therm109(T109B_C,1,1,1,20000,_60Hz,1.0,0.0)
In Edlog use the DC Half Bridge instruction (P4) with a 20 millisecond delay
as shown below. Use P4 in place of P5 in Example 5.2.1.1 (the instructions
that follow P5 to convert the measurement result to temperature are still
required).
1: Excite-Delay (SE) (P4)
1: 1
Reps
2: 25
2500 mV 60 Hz Rejection Range (Delay must be zero)
3: 1
SE
Channel
4: 1
Excite all reps w/Exchan 1
5: 2
Delay (0.01 sec units)
6: 2500
mV
Excitation
7: 3
Loc [V_Vx ]
8: .0004
Multiplier
9: 0.0
Offset
6. Measurement Details
Understanding the details in this section are not necessary for general
operation of the 109B Probe with CSI's dataloggers.
The Therm109 Instruction outputs a 2500 mV excitation and measures the
voltage across the 24.9 K resistor (Figure 6-1). The thermistor resistance
changes with temperature.
EX
HI
AG
G
BLACK
RED
PURPLE
CLEAR
24.9K
Ω
, 0.1%
10K3AI
THERMISTOR
FIGURE 6-1. 109B Thermistor Probe Schematic
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