Sensor Dip Switch Settings; Electrical Noise And Interference - Process Technology DQ15D Instruction Manual

F4, Unit Display Enable
This setting may be set to a zero (0) or a one (1). When set to one (1), the
DQ15D will display either a "C" or an "F", separated by a decimal point.
This indicates that either Celsius or Fahrenheit is being displayed. If the
temperature being measured is greater than +999 degrees, the units are
not shown because the display is limited to four positions.
F5, Temperature Units Conversion
This setting may be set to a zero (0) or a one (1). When set to a zero (0),
the temperature is displayed in degrees Fahrenheit. When set to a one (1),
the temperature is displayed in degrees Celsius.
Conversion from F to C does NOT change set point or alarm upper limit
values. These must be changed manually.
Note: The default setting is zero (0).
F6, Current Output Enable
This setting can be either zero (0), which is OFF, or one (1), which is ON.
When ON, it enables the optional current adder board on the DQ15D.
See page 21 for details on the current output signal.
If the DQ15D is equipped with the optional 4-10 mA output feature, then
setting "F6" to one (1) turns ON this feature. "F6" must be ON before
any calibration can be performed.
Note: The default setting is zero (0). Only active when using either of
the optional 5416 or 5419 boards.

Sensor DIP Switch Settings

5447 or 5416
When using the sensor 5416 or 5447 boards, an "on-board" DIP switch
must also be configured. The DIP switch settings are as follows:
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Sensor DIP Switch:
Selections
Sw1 Sw2 Sw3 Type
OFF OFF OFF 1000 ohm
RTD
ON OFF OFF 100 ohm
RTD
OFF ON OFF voltage
OFF OFF ON current
OFF OFF OFF frequency
(illustration shows DIP switch
setting for 100 ohm RTD)

Electrical Noise and Interference

Process Technology electronic controls are engineered, tested and manu-
factured to conform to Europe's CE levels of electrical noise and inter-
ference found in typical industrial installations. It is always possible for
electrical noise and interference to exceed the level of designed-in pro-
tection. This can happen, for example, if arc or spot-welding equipment
is close to the control or if they share a common power line. It can occur
if flame ignition systems or electrostatic precipitators are in the vicinity of
the control. A more common source of interference occurs when the con-
trol is switching inductive loads such as contactor coils, solenoids or
motors. The collapse of the magnetic field when loads such as these are
switched off can create an electrical "spike" that can cause a malfunction
of the microprocessor used in the control. Even if the control doing the
switching is unaffected, a nearby control may be affected. To eliminate or
minimize this problem, transient suppressors or "snubbers" can be em-
ployed across the inductive load.
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