
IM-P505-02-US
Issue 1
30
UTM20 Series Ultrasonic Transit-time Flowmeters
8.6 Power
Connect power to the screw terminal block in the transmitter.
Low voltage power can use any available conduit hole in the enclosure.
Line voltage AC power must use the right conduit hole, which is aligned with the terminal block on
the AC power board.
Use wiring practices that conform to local and national codes such as The National Electrical Code
Handbook in the U.S.
WARNING
Any other wiring method may be unsafe or cause improper operation of the transmitter
Note:
This transmitter requires clean electrical line power. Do not operate this transmitter on circuits
with noisy components (such as fluorescent lights, relays, compressors, or variable frequency drives).
Do not use step-down transformers from high voltage, high amperage sources. Do not to run signal
wires with line power within the same wiring tray or conduit.
8.7 9 to 28V DC Power
The transmitter may be operated from a 9 to 28V DC source, as long as the source supplies a maximum
of 8 Watts of power.
Connect the DC power to 9 to 28V DC In, power return, and chassis ground, as below .
Note:
DC-powered transmitters are protected from major catastrophe with an internal 2.0 Amp slow-
blow fuse. If this fuse is blown, replace the transmitter or return it to the factory for repair.
IMPORTANT: A Class II DC power supply is required.
Fig. 32 Power supply 9 to 28V DC
External Equipment
Power Supply (9 . . . 28V DC)
Power Supply (Return)
(Acceptable wire sizes: 28 to 12 AWG)
TB400
Switch
or Circuit
Breaker
Chassis Ground