DEA
Engineering Company |
 |
|
| Phone:(951) 552-0102 | Fax:(951) 763-1263 | E-mail: dealigio@deaengineering.com |
Mechanical Installation & Operating Considerations
Electronic Installation & Operating Considerations
DEA MICRO FLOWMETER-ELECTRONIC INSTALLATION AND OPERATING CONSIDERATIONS
1.
A twisted, shielded, 18 gauge, 3 or more conductor cable is recommended
to minimize interference. If the Microflowmeter signal at the electronics
is less than required, use a larger gauge wire. If this does not effect
the desired result, a repeater may be required. The two ground temminals
should be jumpered at the electronics. Power and signal wires should be
shielded. Only one end of the shield should be connected to ground. [Never
use the shield as a signal or power conductor.]
2. When using inductive devices such as relays, motors, or solenoids,
care must be taken to avoid voltage transients which result when these
devices are switched on and off. These transients can often be strong
enough to interfere with [and even damage] system electronics. If the
inductive devices are DC, a suppression diode should be placed across
the coil as shown in Figure 1.
On
AC systems, a type of transient suppression device called a Varistor [MOV]
should be used. The power should be controlled by a solid state relay
which switches at zero voltage. The power supply driving the inductive
devices should not be used to drive the system electronics. The supply
for the electronics should have an AC line filter either integral with
the supply or as a separate module. It is strongly recommended that wires
which control the inductive devices not be bundled over long distances
with sensor signal wires, even if these wires are shielded.