Carlisle Ransburg DynaFlow 77376, Руководство по обслуживанию, Страница: 63 / 96

Flow Too Low -or- Flow Too High
Explanation: These are CHANNEL specific faults.
FLOW TOO HIGH and FLOW TOO LOW faults are issued
if the requested fluid flow cannot be obtained. This typically
means that there is a setup problem, maintenance issue,
or mechanical failure.
These types of faults can be caused by numerous problems.
Most of the more common causes are listed below. Keep
in mind that the controller senses that either too little or too
much material is getting to the applicator and that this is
based on JOB parameter settings and fluid flow feedback
from the flow meters. This troubleshooting section assumes
that the system was previously operating successfully and
then a problem developed. The following is not meant for
initial system setup, however, many of the troubleshooting
procedures described can be used in either case.
1. Material Supply Pressure
• Has the material supply pressure changed?
• What was the supply pressure when the system was
operating properly?
• Is the pressure gauge accurate or reliable?
• Has the fluid delivery system been changed?
• Are there any air leaks in the fluid regulator pilot line?
• Are there any leaks in the fluid lines?
The controller can compensate for small changes in supply
pressure, but changes such as seen with piston pumps
without surge chambers or pressure drop regulators can
be a definite problem.
2. Material Viscosity
• Has the material properties such as viscosity or
temperature changed?
Changes in viscosity alter the way in which it passes through
the fluid metering and control components (regulator, flow
meter, check valves, Y-Block, spiral mix tube, etc.). Typi-
cally, an increased viscosity will require more pressure to
achieve the same flow rate. However, in some cases, as
with thixotropic materials, the viscosity will actually change
as the pressure varies or as the material passes through
the fluid regulator or flow meter. Additionally, the material
may be broken down into smaller particles as it passes
through the fluid delivery system which can also cause
some materials to change their properties as they flow.
The temperature of the fluid can also greatly impact the
flow properties. Make sure that the fluid heaters are func-
tioning correctly if temperature control is being used. If
temperature control is not being used, then evaluate how
ambient temperature may effect the fluid, as it is stored
including the paint kitchen. Also, consider the length of
the recalculating system and how long the material takes
to travel to the applicators.
The amount in which the control response is effected by
changes in fluid properties is also determined by how ag-
gressive the control parameters are set (Kp, Ki, Kd). The
fluid flow response can be observed as discussed in the
"Operator Interface" manual. Also, refer to the "PID Control"
in the "Operation" section of this manual under
3. Fluid Line Restriction
- Has a restriction formed somewhere in
the fluid line?
This could be a pinched paint tube, contamination in the
fluid regulator, spiral mix tube blockage, a sticking check
valve, or a Y block blockage to name a few.
Corrective Action:
An easy way to verify that the system is capable of flowing
at the desired rate is to place the GUN in CLEAN MODE
and trigger the applicator. The CLEAN MODE supplies
maximum control pressure to the fluid regulator. Watch the
flow rate. If the desired flow rate cannot be achieved or
surpassed in CLEAN MODE, it is obvious that it will not be
achievable in control mode. This tests all fluid lines from the
material supply to the applicator. If calibration ports (valves)
are available, such as on 2K fluid panels, try operating the
controller with the calibration valves open. Place containers
under the calibration ports and put the controller in RUN
mode. If operating in AUTO-MATIC MODE, the TRIGGER
signal has to be
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