KROHNE VFM 3100 EN - Manual (Page 13)

1.2.7. VFM 3100 with Remote Electronic Module
The purpose of the remote electronic module is to allow for separa-
tion of the VFM 3100 body and the electronics housing.
This VFM 3100 consists of:
• An electronics housing mounted to a pipe or wall mounting
bracket with up to 15 m (50 ft) of interconnecting cable attached.
• A VFM 3100 body with junction box. The junction box contains
a preamplifier assembly. Refer to Figure 9.
• 1/2 NPT conduit connections are provided on both the housing
and the junction box.
NOTES:
• Mount the VFM 3100 so that the junction box is serviceable.
• The cable is prewired to the junction box to ensure proper
grounding of the shield. It is recommended not to disconnect
the cable from the junction box.
• If the cable must be disconnected, make sure the end labeled
"VFM 3100 End" is positioned at the junction box end.
• If the cable is to be shortened, refer to Table 2 for re-dressing
cable ends.
Installing the Remote Electronics
WARNING: For optimum VFM 3100 performance, the remote signal
cable must be prepared and connected following the procedures
outlined below.
To install the remote electronics as shipped, execute the following
procedure:
• Mount the VFM 3100 as described in the preceding section. Be
sure to mount the VFM 3100 so that the junction box is service-
able.
• Mount the housing. The bracket assembly supplied with the hou-
sing may be mounted directly to a wall or to a 2-inch pipe stand.
• Mount the housing close enough to the VFM 3100 so that the
supplied cable will reach between the VFM 3100 and the housing.
To install remote electronics that must be separated, disconnect the
remote signal cable at housing end as described below.
It is not recommended that you disconnect the VFM 3100 end
(junction-box end).
• Remove electronic compartment threaded cover.
• Unscrew the two captive screws, one on each side of the
electronic module.
• Pull out electronic module far enough to disconnect the
remote signal cable.
• Disconnect the four remote signal wires from the four position
terminal block on rear of the electronic module. See Figure 9.
• Unscrew knurled nut, pull it back onto cable jacket, also pull
rubber bushing onto the cable jacket. Leave these parts on the
cable jacket as they will be used when reconnecting the cable.
• Mount the VFM 3100 as described in the preceding section. Be
sure to mount the VFM 3100 so that the junction box is service-
able.
• Mount the housing close enough to the VFM 3100 so that the
supplied cable will reach between the VFM 3100 and electronic
housing.
• Mount the electronic housing. The bracket assembly supplied
with the housing may be mounted directly to a wall or a 2-inch
pipe stand.
Interconnection Wiring for Remote Electronics
Installation without Conduit:
If the VFM 3100 and electronic housing were NOT separated during
installation, the interconnection wiring is complete.
NOTE: Oxygen cleaned meters are shipped separated.
If Housing End Is Disconnected:
If the VFM 3100 and electronic housing were separated during instal-
lation, follow the procedures below for interconnection wiring.
• Make sure the knurled nut and rubber bushing are on the cable
jacket. Orient the cable so that the end labeled "VFM 3100 End"
is positioned at the VFM 3100 junction box and the "Electronics
End" is positioned at the remote electronics housing.
• If the pre-dressed cable does not look as shown in Table 6, pre-
pare it following the instructions for dressing electronic housing
end of remote signal cable in Table 6 on page 17.
• Take the prepared cable, taking care not to damage the copper
braid, and push it into the connector at bottom of the electronic
housing, as shown in Step 1 of Table 6 on page 17 until it comes
to a stop.
• Ensure that the remote signal cable is pushed in all the way, until
the outer jacket bottoms out inside the connector. Push the
rubber bushing into position, until it sits snug inside the connec-
tor, as shown in Step 2 of Table 6 on page 17.
• Tighten the knurled nut on the connector to create a compression
fit for a good seal.
• Inside the electronic housing, connect the four remote signal wi-
res to the color coded 4-position terminal block on the rear of the
electronic module. See Figure 9 on Page 16.
• Ensure that the remote signal and loop power wires are tucked
under the electronic module. Taking care not to pinch the wires,
place the module in housing over mounting screws. Tighten the
two captive mounting screws.
• Replace threaded housing cover tightly. This will prevent moisture
or other contaminants from entering the compartment.
13
Electrical housing
with digital display/configurator
Locknut
Connector Locking plate
Figure 8. Repositioning the Electrical Housing