Flowserve 1400 Valtek Logix - Manual (Page 18)

46-18 Flowserve Corporation, Valtek Control Products, Tel. USA 801 489 8611
Spool Valve
The spool valve is a four-way directional valve with
precision features to provide optimal control and low air
consumption. To help prevent spool valve malfunction,
the positioner supply air must conform to ISA Standard
S7.3 (a dew point at least 18 degrees below ambient
temperature, particle size below 1 microns, oil content
not to exceed 1 part per million). Flowserve’s standard
coalescing filter is highly recommended to help meet
these requirements.
Small particles, oil that has varnished, corrosion, ice,
burrs and extreme wear could cause the spool valve to
act abnormally. If the spool valve is suspected of
sticking, it can be inspected by performing the following.
1. Make sure the valve is bypassed or in a safe condition.
2. Disconnect the power and air supply to the unit.
3. Remove the spool valve cover by removing the
screw and sliding the cover assembly backwards
until the tab is clear of the slot.
4. Inspect the coalescing filter element in the spool
valve cover for signs of oil, water and debris that may
have come from the air supply. A clean filter is white.
5. Remove the two phillips-head screws holding the
spool valve to the housing. Inspect the free move-
ment of the spool by carefully sliding the block up
and down on the spool about
1 /
4
inch. The block
should slide on the spool with no resistance. Care-
fully remove the block ensuring it is removed con-
centric with the spool.
6. Inspect the block and spool for oil, water, debris and
wear. If oil, water and/or debris are found, the spool
and block can be cleaned with a non-residue cleaner,
lint free cloth and soft bristle brush. If wear is found,
replace the driver module assembly as instructed in
this document.
7. Before reassembly, verify that the three O-rings are
in the counter-bores on the machined platform where
the spool valve block is to be placed.
8. Carefully slide the block over the spool, using the
machined surface of the housing base as a register.
Slide the block toward the driver module until the two
retaining holes line up with the threaded holes in the
base. If resistance is still encountered re-clean both
parts or replace the driver module assembly. Refer
to the
Spare Part Kits section.
Alarms
The Logix 1400 digital positioner has several internal
alarms which monitor electronics operation. An internal
alarm causes the red LED to blink. Alarms differ from
alerts because the action of the positioner may be erratic
during the alarm conditions. Alert warns operations that
a predefined, user configured, condition has occurred
that may require service in the near future. Alarms cause
the red LED to blink, while alerts cause the yellow LED
to blink. Refer to the F
OUNDATION fieldbus documentation
for the handling of FB alerts and alarms.
12-bit A/D Reference Alarm
The Logix 1400 digital positioner utilizes a 12-bit analog-
to-digital converter to acquire stem position readings. If
the precision reference used by the A/D drifts outside
rated tolerances, the 12-bit A/D reference alarm will
become active. A reference error will cause change in
calibration and control readings. If a continuous 12-bit
A/D reference alarm exists, the main PCB assembly
must be replaced. Refer to the
Spare Part Kits section.
1.23 V Reference Alarm
The 1.23 V reference is used by the inner-loop spool
position control. If it drifts outside normal tolerances, the
1.23 V reference alarm will become active. If a continu-
ous 1.23 V reference alarm exists, the main PCB
assembly must be replaced. Refer to the
Spare Part Kits
section.
12-bit D/A Alarm
The Logix 1400 digital positioner utilizes a 12-bit digital-
to-analog converter to send a control signal from the
microcontroller to the inner loop spool positioning circuit.
The output of the D/A converter is independently mea-
sured to verify correct operation. A 12-bit D/A alarm
indicates that the D/A may be malfunctioning. If a
continuous 12-bit D/A Alarm exists, the main PCB
assembly must be replaced. Refer to the
Spare Part Kits
section.
Temperature Alarm
The main PCB assembly contains an ambient tempera-
ture sensor. If the ambient temperature readings goes
outside the operating range, -40
° F to +185 ° F (-40 ° C to
+85 ° C), the temperature alarm will become active. The
red LED will also blink. If this alarm is present and the
ambient temperature reading is incorrect, the main PCB
assembly must be replaced. Refer to the
Spare Part Kits
section.
Hall Sensor Alarm
The Logix 1400 digital positioner uses an inner-loop,
spool-positioning stage. A hall sensor is used for spool
control. If the electronics senses a problem with the
sensor, the hall sensor alarm will activate. Some com-
mon reasons for a hall sensor alarm are loose or missing
cable connection to the collector board assembly or a
broken wire. In the event that the actual hall sensor is
defective, the driver module assembly must be replaced.
Refer to the
Spare Part Kits section.