Bimba PCS - Manual (Page 29)

www.bimba.com Technical Assistance: 800-44-BIMBA 29
Solution: Provide an analog 0-10 VDC command signal that has less than 5 mV of
ripple. Employ proper wiring techniques to ensure signal noise is kept to a
minimum (use shielded cables, proper grounding methods, etc.)
Problem:
Solution: The actuator feedback has excess signal noise.
Ensure that the feedback signal is free from electrical noise. Electro-
Magnetic Interference (EMI) can couple to the feedback signal. Employ
shielded cable between the actuator and the PCS system.
Problem:
Solution: The valves are contaminated.
The valves need rebuilt or replaced. Teflon tape or line contamination can
cause valve leaks if allowed to enter the valve. Use a liquid thread sealant
and a filtration system that is rated for 5 microns.
Problem:
Solution: Possibly Nothing.
The actuators and valves are built to minimize leakage, but not to totally
eliminate it. If a stable positioned actuator drifts toward the edge of the
system deadband, the PCS will pulse to maintain position. If the deadband is
set very narrow, this correction will be more frequent.
Frequently Asked Questions
Question:
Answer: Are there Default Settings for the Deadband, Zero, Span, and Decel settings?
While there are no perfect default settings, the following are used as the
default factory settings.
• Deadband 0.020 VDC (20mV). Check between TP1 and TP2 with SW1
switched in the Set position.
• Decel 1.5 VDC. Check between TP1 and TP3.
• Zero is set to its minimum value (fully CW).
• Span is set to its minimum value (fully CW).