Flowserve APEX A9000 Accord - Manual (Page 15)

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9.1 Grounding screw
The grounding screw, located inside the positioner cover, 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. The grounded
screw must not be used to terminate signal shield wires.
9.2 Electromagnetic compatibility
The Apex A9000 digital positioner has been designed to operate correctly in electromagnetic (EM) fields
found in typical industrial environments. Care should be taken to prevent the positioner from being used in
environments with excessively high EM field strengths (greater than 10 V/m). Portable EM devices such as
hand-held two-way radios should not be used within 30 cm of the device. techniques of the control lines, and route
control lines away from electro-magnetic sources that may cause unwanted noise.
An electromagnetic line filter can be used to further eliminate noise.
In the event of a severe electrostatic discharge near the positioner, the device should be inspected to ensure
correct operability. It may be necessary to recalibrate the Apex A9000 positioner to restore operation.
Ensure proper wiring and shielding
Figure 9. Compliance voltage
9.3 Compliance voltage
Output compliance voltage refers to the voltage limit the current source can provide. A current loop system consists
of the current source, wiring resistance, barrier resistance (if present), and the Apex A9000 impedance.
The Apex A9000 requires that the current loop system allow for a 8.0 - 9.4 VDC drop across the positioner at
maximum loop current.
CAUTION: Never connect a voltage source directly across the positioner terminals. This could cause
permanent circuit board damage.
In order to determine if the loop will sup- port the Apex A9000, perform the following calculation:
Voltage = Compliance Voltage (@Current
max
) – Current
max
( R
barrier
+ R
wire
)
To support the Apex A9000 the calculated voltage must be greater than 9.4 VDC for Apex A9000 HART and 8 VDC
for non-HART.