Notes On Wiring; Notes On Instrumentation-Converter Wiring; Notes On Wiring Of The Lf622*B Type - Toshiba LF620 B Series Instruction Manual

5.3 Notes on Wiring

5.3.1 Notes on Instrumentation-Converter Wiring

• To avoid 2-point grounding, ground the shield of output cable basically at the receiving side.
• Use a grounding wire of IV wire 5.5mm
Do not share a grounding wire with other instruments where grounding current may flow. (An
independent grounding is preferable.)
• Power cable
When a 3-core cable is used: Ground with the FG terminal.
When a 2-core cable is used: Use an external grounding terminal and make the cable as short as possible.
Note that, for a replacement from the Toshiba electromagnetic flowmeter converter LF220 type, the cable
grounding position differs.

5.3.2 Notes on Wiring of the LF622*B Type

• The detector is shipped with a flow rate signal cable and excitation cable. Be sure to use those cables coming
with the detector.
LF622*B
Note: When the cable length exceeds 30m, cables may not be supplied. Check whether the cable is
supplied with the specs.
• The allowable cable length between the detector and converter varies depending on the conductivity of the
operating fluid. Refer to the instruction manual of the combined detector.
• The terminals at the converter side of the attached cables are capped for preventing humidity infiltration. Do
not remove the cap from the cable until immediately before performing wiring connection to the
converter.
• When connecting with the detector, wire the cables in the order of the excitation cable and flow rate signal
cable.
• Because the input cables transmit very delicate signals, pass the excitation cable and input signal cable
separately through a steel conduit tube, keep them away from the large current wiring as far as
possible, and do not install them in parallel.
• The detector side terminal of the attached cable is previously wired at factory. Since the terminal box of the
detector has an air-tightness structure, do not remove the previously wired cable from the detector.
• When replacing the flow rate signal cable and excitation cable, also refer to the instruction manual of the
relevant detector. Order the detector terminal box cover gasket and cable connection gasket from Toshiba or a
Toshiba distributor and be sure to replace the gasket.
2
or more. The size of the external grounding terminal screws is M4.
－ 25 －
6 F 8 A 0 9 9 7