Grounding The Housing; Connecting To The Multi-Variable Transducer (Mvt) - Emerson ControlWave EFM Instruction Manual

2.4.1 Grounding the Housing

2.4.2 Connecting to the Multi-Variable Transducer (MVT)

Revised Dec-2013
The ControlWave EFM enclosure includes a ground lug. Once you have
installed the unit, run a ground wire (#4 AWG max wire size) between
the ground lug (see Figure 2-4) and a known good earth ground. As an
added precaution, run a #14 AWG wire from SCM power connector
TB1-3 (chassis ground) to the same known good earth ground. For more
information on grounding see the ControlWave Grounding Supplement
(S1400CW):
Additional grounding guidelines include:
 Use stranded copper wire (#4 AWG) to earth ground, and keep the
length as short as possible.
 Clamp or braze the ground wire to the ground bed conductor
(typically a stranded copper AWG 0000 cable installed vertically or
horizontally).
 Using a high-wattage soldering iron, tin the wire ends with solder
before you insert them into the chassis ground lug.
 Run the ground wire so that any routing bend in the cable has a
minimum radius of 12-inches below ground and 8-inches above
ground.
The ControlWave EFM's multivariable transducer (MVT) secures to the
bottom of the enclosure. The MVT pressure assembly connects to the
process manifold either directly or by tubing. Within the body of the
transducer, metal diaphragms are exposed to the gas. Solid-state strain
gauge sensors in the neck of the transducer measure the pressure applied
to the diaphragms and produce proportional electrical signals.
The neck of the transducer extends into the bottom of the enclosure,
with the body of the transducer outside the enclosure. The MVT cable
connector is factory mated with System Controller module connector
P2.
The MVT provides connection ports on the process flange as the
standard arrangement. Optional manifold blocks may also be specified.
Figure 2-9 details MVT process flange and optional manifold block
connector mounting dimensions.
Standard Process Flange for MVT – Two process flanges containing
the connection ports are assembled to the transmitter. Port designations
(L and H) are stamped on the body of the flanges. Ports accept ¼-18
NPT pipe connections to 2-1/8 in. centers for connection to orifice taps
or a standard three-valve manifold. These process flange connections
are illustrated at the top of Figure 2-9.
Installation
ControlWave EFM Instruction Manual
2-13