Logix
®
520MD+ and 510+ Digital Positioners FCD LGENIM0105-15-AQ – 05/16
6
in this instruction could drastically affect performance and be hazard-
ous to personnel and equipment, and may void existing warranties.
Between actuator and valve there are moving parts. To avoid injury
Flowserve provides pinch-point-protection in the form of cover plates,
especially where side-mounted positioners are fitted. If these plates are
removed for inspection, service or repair special attention is required.
After completing work the cover plates must be refitted.
Logix 500+ positioner repair is limited to the replacement of sub-as-
semblies and circuit boards with Flowserve-manufactured replacements
as outlined in this manual.
c
DANGER:
Substitution of with non-factory positioner components
may impair intrinsic safety.
a
CAUTION:
Before products are returned to Flowserve for repair
or service, Flowserve must be provided with a certificate which
confirms that the product has been decontaminated and is clean.
Flowserve will not accept deliveries if a certificate has not been
provided (a form can be obtained from Flowserve).
Apart from the operating instructions and the obligatory accident pre-
vention directives valid in the country of use, all recognized regulations
for safety and good engineering practices must be followed.
1.8 Disposal
Electronic components are contained inside the positioner.
NOTICE:
Potential hazards and their sources are under the opera-
tor‘s influence. The operator must observe national and international
environmental conditions for positioner removal from the valve and
cleaning. Permissible limit values must be maintained to ensure suitable
protective measures; service personnel must be properly instructed in
performing the disassembly and reassembly procedure.
Metal parts should be scrapped, with the remaining materials disposed
of according to national regulations.
PRINCIPLES OF OPERATION
1.9 Basic Operation
The Logix 500+ digital positioner is a two-wire 4-20 mA input digital
valve positioner which uses the HART protocol to allow two-way remote
communications. The positioner is completely powered by the 4-20 mA
input signal. Start-up current must be at least 3.8 mA. The positioner
is configurable through the local user interface, hand-held or DTM.
The Logix 500+ positioner can control both double- and single-acting
pneumatic actuators with linear or rotary mountings.
The Logix 500+ digital positioner is an electronic and pneumatic closed-
loop feedback instrument. Figure 1 shows a schematic of a Logix 500+
positioner installed on a single-acting linear actuator for air-to-open
action. Figure 2 shows the double acting option.
1.10 HART
The Logix 500+ receives power from the two-wire, 4-20 mA input
signal. However, since this positioner utilizes HART communications,
two sources can be used for the command signal: Analog and Digital.
In Analog source, the 4-20 mA signal is used for the command source.
In Digital source, the level of the input 4-20 mA signal is ignored (used
only for power) and a digital signal, sent via the HART communication
protocol, is used as the command source. The command source can
be accessed with ValveSight software, the HART 375 communicator, or
other host software. See section 11 HART COMMUNICATION for more
information.
1.11 Position Definition
Whether in Analog or Digital Source, The position at 0% is always
defined as the valve in a closed position and 100% is always defined as
the valve in an open position. In Analog Source, the 4-20 mA signal is
converted to a position (in percent). During loop calibration, the signals
corresponding to 0% and 100% are defined.
