Yokogawa 2-Wire Dual Channel Transmitter/Analyzer FLXA21 - Manual (Page 32)

<2. WIRING AND INSTALLATION>
2-5
IM 12A01A02-01E 5th Edition : Oct. 31, 2013-00
CAUTION
The FLXA21 is used with a DC power supply. Do not use an alternating current or 100 volt mains
power supply.
The cable leading to the distributor (power supply) supplies the power to and transmits the output
signal from the FLXA21.
Use a two conductor shielded cable with a minimum cross sectional area of 1.25 mm
2 and an
outside diameter of 6 to 12 mm. The cable gland supplied with the instrument is compatible with
these diameters.
Terminal screw size is M4, and torque of screw up is 1.2 N•m.
Pin terminal, ring terminal and spade terminal can be used for the power supply terminals in the
plastic housing and the stainless housing, and the grounding terminal in the plastic housing. For
the grounding terminal on the stainless steel case, ring terminal should be used.
Pin terminal: pin diameter: max. 1.9 mm
Ring and spade terminal: width: max. 7.8 mm
CAUTION
Cables that withstand temperatures of at least 60°C should be used for wiring.
CAUTION
Always place the shield cover over the power supply and contact terminals for safety reasons
and to avoid interference.
2.4.1 Grounding
The way of connecting the grounding terminal varies depending on whether the housing is plastic
or stainless steel.
For the safety of the user and to protect the instrument against interference, the converter
housing must always be connected to a class D ground (a ground resistance of 100 ohm or less).
CAUTION
The minimum cross sectional area of the protective grounding cable should be 0.75 mm 2 .
l Grounding the plastic housing
Connect a single separate cable for grounding to the terminal block in the housing (Figure 2.7A).
Use a cable with an outer diameter of 3.4 to 7 mm.
Since the cable is very thin, set the sleeve inside the standard cap of the cable gland and pass
the cable through it. Sleeves are supplied with cable glands (Figure 2.4).
When connecting the converter to a distributor, connect the shield of a double-core shielded
cable to the terminal on the terminal block in the converter. Do not connect the shield to the
ground terminal in the distributor.
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