KROHNE VFM 3100 EN - Manual (Page 30)

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Number of Connectors Letter Code Color Description
2 R Red Loop +
B Blue Loop -
2 Y Yellow Scaled Pulse Out +
G Green Scaled Pulse Out -
4 B Brown Sensor + or Preamp Out +
R Red Preamp Power +
O Orange Preamp Power -
Y Yellow Sensor - or Preamp Out -
Preamplifier
Extended temperature range sensor
and remote standard range sensor
Standard temperature range sensor
Preamp
power
Preamp
power
Flow
measurement
output
Pulse output
Pulse
(switch closure)
4-20 mA HART
Electronic module
Input
Buffered
vortex
signal
STD
EXT
4.2.1. Electronic Module Removal
• Remove power from the VFM 3100.
• Remove electronic module compartment threaded cover.
• Unscrew the two captive screws, one on each side of the
electronic module.
Standard Temperature Range VFM 3100
• Pull the electronic module out of the housing far enough to be
able to disconnect the brown and yellow sensor leads from the
terminal block on the back of the electronic module. Disconnect
the four output signal leads (red [+] and blue [–], and yellow and
green) at the two terminal blocks on the electronic module.
See Figure 17.
• For remote mounted VFM 3100, remove all four preamplifier
wires from the terminal block. Refer to Figure 18.
• Remove the electronic module from housing.
NOTE: Do not cut the plastic tie wraps.
Figure 16. VFM 3100 Block Diagram
Table 10. Electronic Module Terminal Block Connections
Extended Temperature Range VFM 3100
The Extended Range electronic module has a preamplifier mounted
under the electronic module. Do not dislodge the preamplifier.
• Pull the electronic module out of the housing far enough to
be able to disconnect the four preamplifier leads (brown-red-
orange-yellow cable) from the terminal block on the electronic
module and the four signal leads (red-blue, yellow-green).
See Figure 18.
• Remove the electronic module from the housing
4.2. Electronic Module
The electronic module is made up of three printed wiring assemblies
(PWAs) and two captive screws. The electronic module is housed
in the transmitter housing opposite the side labeled “FIELD TERMI-
NALS.” On the back of the module are three terminal blocks.
See Table 10 for a summary of the terminal block connections.