1
Electricalconnectionslabel
The DPA Series of instruments are often customised specifically for
your application. Check the label on top of the case for the correct
connections.
Alarmconnections
The DPA has a high inbuilt immunity to noise spikes caused by
switching inductive loads like solenoids or relay coils. However, it
is important to use suppression capacitors across inductive loads
to preserve the relay contacts and to reduce the effect of switching
spikes on nearby circuits.
The alarm outputs are dual SPDT relay contacts with built in
suppression capacitors fitted across the normally open and common
contacts.
Cablepreparationandinstallation
For effective protection from electromagnetic noise, all signal cables
must be shielded, or located on conductive trays or in conduits.
Use 18 AWG Cu Wire rated for temperatures above 0 °C Only,
tighten to 4. lbIn. Strip wires to mm from the ends. Use a suitable
ferrule for multistranded wires (do not solder).
•CalibrationandSetup
General
The SET (setpoint) and DB (deadband) adjustments control the
setpoint and hysteresis for each alarm channel. Internal jumpers
control the alarm type and relay coil energisation. For best results,
ensure that the unit has reached operating temperature before
calibrating.
The DPA/RTD also has a potentiometer adjustment to compensate
for component variations in the lead length compensation circuit.
Although this control is unlikely to need adjustment, the procedure is
given below.
