■External Connections
Terminal box
Ⅳwire
5.5mm2 or more
Grounded with 100Ω or less ground resistance
Thick walled steel conduit
Detector
Signal cable
Excitation cable
Digital I/O cable
Power supply (CVV)
Power supply
Current output (4 to 20mA)
Digital input 2 (opt.)
Digital input 1 (opt.) (20 to 30 Vdc)
Digital output 4 (opt.) Digital output 3 (opt.) Digital output 2 (opt.)
Digital output
Figure 6. LF502/LF232*F flowmeter Wiring Diagram
■Wiring Precautions
(1)Be sure to use thick walled steel conduit (22 mm) for signal and excitation cable wiring between the detector and converter. The conduit screw is R (PT)1/2. Use flexible conduits at the cable outlets of the detector as needed.
(2)Make the grounding wire as short as possible. Do not use a common ground shared with other equipment where earth current may flow. An independent earth ground is recommended.
(3)The meter may affect its accuracy when the electric potential of measurement fluid is unstable condition.
•Make the piping of the upstream side and downstream side the same material.
•When the material of next pipes are conductive like metal, use a 5.5mm2 or larger core cable for grounding of detector and wire it at 2 places as follows.
•Between Grounding terminal at detector body and Grounding ring at upstream side.
•Between Grounding terminal at detector body and Grounding ring at downstream side.
•Between Grounding terminal at detector body and Grounding (100 ohm or less).
(4)DO1 to DO4 and DI1 to DI2 use the same common terminal (COM). This COM can not connect to other instruments that have their own ground terminal (Power supply for connecting to DI or DO, etc...). Need to wire separately.
• When the material of next pipes are
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