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Instruction Manual
LIQ-MAN-245
Section 2: Troubleshooting
2.1
Troubleshooting
To check the toroids, recall the data obtained during the Calibration Verification Process
(see Section 1.6). With the sensor empty of process fluids (preferably also clean and dry),
reapply the resistance to the yellow Cal Loop wires in the junction box. The reading should be
within + 20% of its original value.
To check the RTD, disconnect RTD leads of the interconnecting cable (PN 23909-00) and
measure the resistance across the white and one of the red RTD wire terminals in the junction
box. See Figure 1-4. The resistance value should be close to the applicable value shown in
Table 2-1.
Finally, check the sensor for open connections and short circuits. Be sure to disconnect the
cable (PN 23909-00) before checking. See Table 2-2 and Figure 2-1.
Table 2-2. Sensor Wire Resistance Values with Instrument Cable Disconnected
(instrument leads and gray wire connected to terminal block, see Figure 2-1)
Connection (wire or component connections)
Each twisted pair, WHITE to GRAY
YELLOW to YELLOW
WHITE to WHITE
RED to YELLOW
RED to each WHITE
YELLOW to each WHITE
ALL except RED to housing EARTH screw
RED to housing EARTH screw
Troubleshooting
Table 2-1 Resistance Values for Pt 100 and Pt 1000 RTDs
Temperature
(°C/°F)
18 / 64.4
19 / 66.2
20 / 68.0
21 / 69.8
22 / 71.6
23 / 73.4
24 / 75.2
25 / 77.0
26 / 78.8
27 / 80.6
Resistance (Ohms)
Pt 100
Pt 1000
106.9
1069
107.3
1073
107.7
1077
108.1
1081
108.4
1084
108.9
1089
109.2
1092
109.6
1096
110.0
1100
110.4
1104
Resistance
0.4 to 0.9 Ω
0.1 to 0.5 Ω
> 20 MΩ
> 20 MΩ
> 20 MΩ
> 20 MΩ
> 20 MΩ
0.1 to 0.5 Ω
Troubleshooting
June 2017
9
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