FloBoss 407 Instruction Manual
Rev 5/00 B-1
APPENDIX B — MULTI-VARIABLE SENSORS
B.1 SCOPE
This appendix describes the Multi-Variable Sensor (MVS) devices, which provide differential pressure,
static pressure, and temperature inputs to the FloBoss 407 for orifice flow calculation. Topics covered
are:
Information Section Page Number
Description B.2 B-1
MVS Mounting B.3 B-3
Field Wiring B.4 B-7
MVS Lightning Protection B.4.1 B-11
RTD Wiring B.4.2 B-11
Configuration B.5 B-13
Calibration B.6 B-14
MVS Troubleshooting and Repair B.7 B-18
Lockup of an MVS B.7.1 B-18
MVS Displays Letters Instead of Numbers B.7.2 B-18
Specifications B.8 B-19
B.2 DESCRIPTION
The MVS is available either as an integral part (MVS205 only) of the FloBoss 407 or as a remote-
mounted unit. There are two Remote MVS products available: the MVS101R (see Figure B-1) and the
MVS205R (see Figure B-2). The remote products include an electronics head in addition to a sensor
body, which is common to both the integral and remote versions. The electronics head contains an
interface electronics circuit that provides the communications link between electronics in the sensor
body and the FloBoss 407.
The MVS interface electronics provide the communications link between the FloBoss 407 and the
sensor body. The interface electronics controls communications with the sensor module, does scaling
of process variables, aids calibration, provides storage of operating parameters, performs protocol
conversion, and responds to requests from the FloBoss 407.
The MVS sensor body contains electronics that sends data to the interface circuit approximately every
100 milliseconds. The interface circuit maintains an average of the last five readings for each variable:
differential pressure, static pressure, and temperature. The FloBoss 407 polls the MVS interface circuit
at a scan rate that is determined by the number of sensors present (at worst once a second with four
MVS devices present), and uses the most recent average for each variable as inputs to the flow
calculation.
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