Flowserve Logix 3200MD User Manual

®
User instructions - Digital Positioner 3200MD LGENIM0059-01 10/08
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6.1 4-20 mA Command Input Wiring
Verify polarity when making field termination connection. The Logix
3200 is reverse polarity protected. Wire 4-20 mA current source to
the input terminal labeled 4-20 mA Input on the user interface board
(see Figure 6). Never connect a voltage source directly across the
Logix 3200MD terminals. The current must always be limited for
4-20 mA operation. Minimum operating current is 3.6 mA.
The input loop current signal to the Logix 3200MD digital positioner
should be in shielded cable. Shields must be tied to a ground at only
one end of the cable to provide a place for environmental electrical
noise to be removed from the cable. In general, shield wire should
be connected at the source.
NOTE: The Logix 3200MD positioner carries an intrinsically safe bar-
rier rating of 100 mA. Input currents should not exceed 100 mA.
6.2 Grounding Screw
The green grounding screw, located inside the termination cap,
should be used to provide the unit with an adequate and reliable
earth ground reference. This ground should be tied to the same
ground as the electrical conduit. Additionally, the electrical conduit
should be earth grounded at both ends of its run.
c
WARNING: The green grounding screw must not be used to
terminate signal shield wires.
6.3 Compliance Voltage (See Figure 7)
Output compliance voltage refers to the voltage limit that can be
provided by the current source. A current loop system consists of
the current source, wiring resistance, barrier resistance (if present),
and the Logix 3200MD positioner impedance. The Logix 3200MD
digital positioner requires that the current loop system allows for
a 10.0 VDC drop across the positioner at maximum loop current.
The 10.0 VDC drop across the Logix 3200MD positioner terminals
is generated by the positioner from the 4-20 mA loop current input.
The actual voltage at the terminals varies from 9.8 to 10.0 VDC
depending on the current mA signal, HART communications, and
ambient temperature.
c
WARNING: Never connect a voltage source directly across
the positioner terminals. This could cause permanent circuit
board damage.
Determine if the loop will support the Logix 3200MD digital posi-
tioner by performing the following calculation.
Voltage = Compliance Voltage (@Current
max
) –
Current
max
•(R
barrier
+R
wire
)
Equation 1
The calculated voltage must be greater than 10 VDC in order to
safely support the Logix 3200MD digital positioner.
Example:
DCS Compliance Voltage = 19 VDC
R
barrier
= 300 Ω
R
wire
= 25 Ω
Current
max
= 20 mA
Voltage=19VDC–0.020A•(300Ω+25Ω)=12.5VDC
The voltage 12.5 VDC is greater than the required 10.0 VDC; there-
fore, this system will support the Logix 3200MD digital positioner.
The Logix 3200MD positioner has a worst case input resistance
equivalent to 500 Ω at a 20 mA input current.
6.4 Cable Requirements
The Logix 3200MD digital positioner utilizes the HART Commu-
nication protocol. This communication signal is superimposed
on the 4-20 mA current signal. The two frequencies used by the
HART protocol are 1200 Hz and 2200 Hz. In order to prevent
Figure 7: Compliance Voltage
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Flowserve Logix 3200MD Specifications

General

Brand	Flowserve
Model	Logix 3200MD
Category	Valve Positioners
Language	English