Flowserve DFC17 - Manual (Page 5)

WCAIM2026 DataFlo Digital Electronic Controller DFC17 Installation, Operation and Maintenance Instructions 5
1.2.1 Temperature
Operating solid state electronic equipment near or beyond
its high temperature ratings is the primary cause for most
failures. It is, therefore, very important that the user be
aware of and take into consideration, factors that affect the
temperature at which the electronic circuits will operate.
Operating an electronic device at or below its low
temperature rating generally results in a unit operating
poorly or not at all, but it will usually resume normal
operation as soon as rated operating temperatures are
reached. Low temperature problems can be easily cured
by addition of a thermostatically controlled heater to the
unit’s housing.
The Worcester/McCANNA DataFlo Digital Electronic
Controller is rated for operation between -40°F (with
heater and thermostat) and 160°F. When using the
Controller inside the Worcester/McCANNA 75 Series
actuators, a maximum ambient temperature of 115°F is
required to ensure the circuit board maximum
temperature of 160°F is not exceeded.
Temperature Ranging allows the user to specify the actual
process temperature conditions within the stipulated range
of the measuring element, i.e., RTD or thermocouple. The
control range can be as little as 50°C or 100°C
respectively, or to the full range of the measuring device.
For temperatures above 600°C, consult factory.
1.2.2 Humidity
Most electronic equipment has a reasonable degree of
inherent humidity protection and additional protection is
supplied by the manufacturer, in the form of moisture
proofing and fungicidal coatings.
Such protection, and the 3 to 4 watts of heat generated
by the circuit board assembly, will generally suffice for
environments where the average relative humidity is in
the area of 80% or less and ambient temperatures are in
the order of 70°F average. Where relative humidity is
consistently 80 to 90% and the ambient temperature is
subject to large variations, consideration should be given
to installing a heater and thermostat option in the
enclosure. The heater should not increase the enclosure
temperature to the point where the circuit board assembly
temperature rating of 160°F is exceeded.
In those instances where the internal heater would bring
the circuit board’s operating temperature near or above its
maximum rating, the user might consider purging the
enclosure with a cool, dry gas. The initial costs can
usually be paid off quickly in the form of greatly extended
equipment life, low maintenance needs, and much less
process downtime.
1.2.3 Input Circuit Noise Protection
Shielded wiring should be used for all setpoint and
process signal input circuit wiring regardless of length.
With separately housed Controllers, the wiring from the
feedback potentiometer to the remote Controller, would
be considered as signal input wiring
and should also be
shielded wire.
The shields should never be used in place of one of the
input wires, and the shields should be grounded to
equipment housings at one end of the wiring run only.
Grounding both ends of shielding can eliminate the
shielding benefits because of current ground loops. If two
or more shielded cables come to the Controller from
different locations, ground the shields at the Controller.
2.0 DataFlo ELECTRONIC
CONTROLLER CIRCUIT BOARD
2.1 General
Figure 1 defines the location of major components and wires
from the Controller Board to terminal strip connections. The
Digital Controller Board is factory wired to the terminal strip
either per Figure 2, Figure 3, or Figure 4, as found in Section 3.0,
depending on power circuit voltage.
The feedback potentimeter leads are factory connected to the
terminal block (TB1) on the Digital Controller Board.
2.2 Circuit Board Configurations
The Controller circuit board is factory supplied in one of several
possible configurations:
A. The Controller circuit board will accept one of the
following setpoint signal inputs, depending on the circuit
board ordered:
• 4–20 mA
• 1–5 mA
• 10–50 mA
• 0–5 VDC
• 0–10 VDC
• 135 ohm pot
• 1000 ohm pot
In addition, the setpoint value can be set remotely via the
RS 485 interface, or locally with the circuit board
switches. When the setpoint is entered locally, all other
means of entering the setpoint are temporarily disabled.
Flow Control Division
Worcester Actuation Systems