Instruction Manual
D103785X012
Wiring Practices
June 2017
13
Ccable = the capacitance of the cable used (see table 2‐1)
The following example shows how to calculate the cable length for a Foxboro
t
I/A control system (1988) with a C
master
of 50, 000 pF and a Belden 9501 cable with characteristic capacitance of 50pF/ft.
Length(ft) = [160,000 - 50,000pF]
[50pF/ft]
Length = 2200 ft.
The HART communication cable length is limited by the cable characteristic capacitance. To increase cable length,
select a wire with lower capacitance per foot. Contact your
for specific information relating to
your control system.
Remote Travel Sensor Connections
The DVC6005 HW2 base unit is designed to receive travel information via a remote sensor. The remote can be any of
the following:
D
Emerson Automation Solutions supplied DVC6015, DVC6025 or DVC6035 remote feedback unit; refer to the
DVC6005 Series Remote Mount Digital Valve Controller quick start guide (
) that ships with the
product,
D
An under‐traveled 10 kOhm potentiometer used in conjunction with onboard 30 kOhm resistor, or
D
A potentiometer used in conjunction with two fixed resistors (potentiometer travel is the same as actuator travel).
WARNING
Personal injury or property damage, caused by wiring failure, can result if the feedback wiring connecting the base unit
with the remote feedback unit shares a conduit with any other power or signal wiring.
Do not place feedback wiring in the same conduit as other power or signal wiring.
Note
3‐conductor shielded cable, 22 AWG minimum wire size, is required for connection between base unit and feedback unit.
Pneumatic tubing between base unit output connection and actuator has been tested to 91 meters (300 feet). At 15 meters (50
feet) there was no performance degradation. At 91 meters there was minimal pneumatic lag.
Using an External 10 kOhm External Potentiometer as a Remote Travel Sensor
Note
Potentiometer travel must be between 1.3 and 1.6 times greater than the actuator travel. For example: if an actuator has a travel
of 9 inches, then a linear potentiometer must be selected with a rated travel between 11.7 and 14.4 inches. The resistive element
must be tapered from 0 kOhm to 10 kOhm over rated travel of the potentiometer. The actuator will only use 63 to 76 % of the
potentiometer rated travel.
