Fisher FIELDVUE DVC6200 Instruction Manual page 17

Instruction Manual
D103409X012
CAUTION
The magnet assembly material has been specifically chosen to provide a long‐term stable magnetic field.
However, as with any magnet, care must be taken when handling the magnet assembly. Another high powered magnet
placed in close proximity (less than 25 mm) can cause permanent damage. Potential sources of damaging equipment
include, but are not limited to: transformers, DC motors, stacking magnet assemblies.
CAUTION
General Guidelines for use of High Power Magnets with Positioners
Use of high power magnets in close proximity to any positioner which is operating a process should be avoided. Regardless
of the positioner model, high power magnets can affect the positioner's ability to control the valve. Technicians should
avoid the use of high power magnets in close proximity with any positioner.
Use of Magnetic Tools with the DVC6215
D Magnetic Tip Screw Drivers – Magnetic tip screw drivers can be used to work on the DVC6215. However, they should
not be brought in close proximity to the magnet assembly (located at the back of the instrument) during process
operations.
D Calibrator Strap Magnets – These are high power magnets used to hold 4-20 ma calibrators.
Normally, these calibrators would not be used while an instrument is controlling the process.
High power magnets should be kept at least 15 cm (6 inches) from the DVC6215.
Note
As a general rule, do not use less than 60% of the magnet assembly travel range for full travel measurement. Performance will
decrease as the assembly is increasingly subranged.
The linear magnet assemblies have a valid travel range indicated by arrows molded into the piece. This means that the hall sensor
(on the back of the DVC6215 housing) has to remain within this range throughout the entire valve travel. See figure 2‐8. The linear
magnet assemblies are symmetrical. Either end may be up.
Figure 2‐8. Travel Range
VALID TRAVEL RANGE
50 mm (2 INCH)
SHOWN
MAGNET ASSEMBLY
(ATTACHED TO VALVE STEM)
X0126
INDEX MARK
Installation
May 2013
17