48
Micro Motion
®
Model D and DT Sensors Instruction Manual
Troubleshooting
continued
c. Use a DMM to measure resistance across wire pairs at the
transmitter end of the cable. See table on page 48.
• If the measured value is within the range listed in the table,
reconnect wiring and restore power to the transmitter.
• If the measured resistance is outside the range listed in the table,
repeat the measurements at the sensor junction box.
-
If the sensor is a
not
a D600, refer to the “Nominal resistance
ranges” table below.
-
If the sensor is a D600, refer to the table and illustration on
page 49.
-
If resistance values measured at the sensor are also outside the
range listed in the table, the sensor might be faulty.
Cross-section of cable with drain wires
Cable jacket
Wire sets
Wire sets
Drain wire
(one for each wire set)
Table 6. Nominal resistance ranges for flowmeter circuits (for all D and DT sensors except the D600)
Notes
• Disconnect wires from terminals before checking resistance values.
• Temperature-sensor value increases 0.38675 ohms per °C increase in temperature.
• Nominal resistance values will vary 40% per 100 °C. However, confirming an open coil or shorted coil is more important than
any slight deviation from the resistance values presented below.
• Resistance across blue and gray wires (right pickoff circuit) should be within 10% of resistance across green and white wires
(left pickoff circuit).
• Actual resistance values depend on the sensor model and date of manufacture.
• Reading across wire pairs should be steady.
Circuit
Wire colors
Sensor terminals*
Nominal resistance range
Drive coil
Brown to red
1 to 2
8 to 2650
Ω
Left pickoff
Green to white
5 to 9
16 to 300
Ω
Right pickoff
Blue to gray
6 to 8
16 to 300
Ω
Temperature sensor
Orange to violet
3 to 7
100
Ω
at 0 °C + 0.38675
Ω
/ °C
Lead length compensator
Yellow to violet
4 to 7
100
Ω
at 0 °C + 0.38675
Ω
/ °C
* For transmitter terminal designations, refer to the table below. For D600 sensors, see the illustration and table on page 49.
Summary of Contents for Micro Motion
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