7
CAUTION: Make sure power is OFF when connecting or disconnecting any
cables or wires to or from the system.
NOTE: The (+) and (-) power inputs are each protected by a 300mA
(DPC04/07/14/17/27/47) and 750mA (DPC57/67/77) (medium time-lag) reset-
table fuse. If a shorting condition or polarity reversal occurs, the fuse will cut
power to the fl ow controller circuit: disconnect the power to the instrument,
correct the faulty condition, and reconnect the power. The fuse will reset once
the faulty condition has been corrected.
3.2 Analog Set Point Signals Connections
CAUTION: When connecting the source signals to the input terminals, do not
exceed the rated values shown in the specifi cations (see Section 5). Failure
to do so might cause damage to this device or signal source equipment.
Be sure to check if the wiring and the polarity of the power supply are
correct before turning the power ON. Wiring error may cause damage or
faulty operation.
DPC series Mass Flow Controllers are equipped with calibrated 0-5Vdc, 0-10Vdc or 4-20
mA set point input signals. These linear input signals represents 0-100% of the fl ow con-
troller’s full scale range. The user may select the desired input analog interface type using a
local OLED/Joystick interface or via digital communication interface.
For 0-5 VDC, 0-10 VDC or 4-20 mA input signal connection:
External Input Plus (+) ------------------------- pin 3 of the 8-pin Mini-DIN connector
External lnput Minus (-) ------------------------- pin 4 of the 8-pin Mini-DIN connector
When 0-5 or 0-10 Vdc input is selected the instrument input impedance is about
100 KOhm. When 4-20 mA input is selected the instrument is functioning as current sink-
ing device with input impedance about 250 Ohm.
NOTE: The Analog interface source must be selected (see Section 6.4.15.8),
in order to control fl ow rate via analog input signal connections.
CAUTION: If nothing is connected to Pin 3, and the controller's set point
source is set for analog control, the instrument may generate random fl ow
rate values. When 0-5 or 0-10 Vdc input signals are selected as the source
of the set point, make sure Pin 3 is driven by low impedance source of the voltage.
Do not apply to Pin 3 voltages above 12 Vdc. Doing so will damage input
circuitry. Do not connect instrument input to "loop powered" signal sources,
as they usually powered with power supplies above 12 Vdc and will
damage instrument.
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