ABB Endura AZ20 series

Combustion Oxygen Monitor
Endura AZ20 Series Probe 3 Troubleshooting – Quick Checks
8 IM/AZ20M–EN Rev. B
3.5 Checking the Cell Isolation
Referring to Fig. 3.5:
1. At the 9-way terminal block A, check the resistance from
the probe’s red (Cell +) connection B to the probe body
C.
2. Check that the cell + connection is isolated from the probe
body earth. If it is not isolated, check for short-circuits to
earth in the probe’s internal wiring.
3. With the cell at ambient temperature, the measured
resistance should be > 20 k.
If the measured resistance is within range, proceed to
Section 3.6.
If the measured resistance is out of range, replace the cell
assembly – refer to Section 5.7, page 16.
3.6 Checking the ACJC Resistance (AZ20 Probe Only)
Referring to Fig. 3.6:
1. At the 9-way terminal block A, check the resistance
(related to ambient temperature) at the probe’s ACJC
(PT1000 temperature sensor) B across terminals C.
2. The measured resistance should be within the ranges
shown in Table 3.3.
3. If the measured resistance is out of range, replace the
PT1000 temperature sensor – refer to Section 5.12, page
35.
If the measured resistance is within range, proceed to
Section 4.
Fig. 3.5 Cell Isolation
A
B
C
Fig. 3.6 Checking the ACJC Resistance
C
A
B
°C 0.0 –1.0 –2.0 –0 –4.0 –5.0 –6.0 –7.0 –8.0 –9.0
-20 921.6
-10 960.9 956.9 953.0 949.1 945.2 941.2 937.3 933.4 929.5 925.5
0 1000.0 996.1 992.2 988.3 984.4 980.4 976.5 972.6 968.7 964.8
°C +0.0 +1.0 +2.0 +3.0 +4.0 +5.0 +6.0 +7.0 +8.0 +9.0
0 1000.0 1003.9 1007.8 1011.7 1015.6 1019.5 1023.4 1027.3 1031.2 1035.1
10 1039.0 1042.9 1046.8 1050.7 1054.6 1058.5 1062.4 1066.3 1070.2 1074.0
20 1077.9 1081.8 1085.7 1089.6 1093.5 1097.3 1101.2 1105.1 1109.0 1112.8
30 1116.7 1120.6 1124.5 1128.3 1132.2 1136.1 1139.9 1143.8 1147.7 1151.5
40 1155.4 1159.3 1163.1 1167.0 1170.8 1174.7 1178.5 1182.4 1186.2 1190.1
50 1194.0 1197.8 1201.6 1205.5 1209.3 1213.2 1217.0 1220.9 1224.7 1228.6
60 1232.4 1236.2 1240.1 1243.9 1247.7 1251.6 1255.4 1259.2 1263.1 1266.9
70 1270.7
Table 3.3 Resistance Values for PT1000 Element at Ambient Temperature (–20 to 70 °C [–4 to 158 °F])