Yokogawa 415 Steam and Gas - Manual (Page 73)

7. INSTALLATION
7.1 GENERAL
Terminal designations for the Model 415 Flow Computer are given on the
following pages. The cutout hole in the panel should be 5.5" (139mm) wide x
2.6" (67mm) high. Two side clips are supplied to secure the instrument into the
panel.
A case earthing point is provided via an earth lug on the side of the case. Note
that this earthing point is for the case only and there is complete electrical
isolation between this point and all electronic circuits. For EMC purposes, or
when the instrument is connected to mains, this point must be connected to a
good earth using a multi-stranded, braided wire or strap. All relay outputs are
totally isolated from the case and from the internal circuitry.
A Supply Output voltage is provided to power sensors. This output will provide a
regulated voltage of 8 to 24 volts and the voltage is adjustable by means of the
potentiometer on the rear panel. Maximum current is 65mA and the instrument
comes with the voltage factory set at 24 Volts. When the instrument is powered
from a DC power source, the maximum output voltage on the Supply Output is
the DC Input Voltage less 3.5 volts.
The instrument will operate from either 14 - 28 volts DC or from the mains. The
mains voltage is factory set to either 95 - 135 VAC (110 VAC nominal) or 190 -
260 VAC (220 VAC nominal). An internal mains transformer provides full
isolation between the mains and the electronic circuits.
The DC Ground terminal 12 provides a common ground for the 14 - 28 Volt
power input, the 8 - 24 Volt output and the pulse output.
It is good practice to use shielded cables for all signal connections to the Model
415. Care must be taken to separate signal cables from power cables so as to
minimise interference.
Overall shields should be connected to the case earth at the instrument end only.
This connection should be as short as possible and connected to the earthing lug
on the side of the case.
Installation 71