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M.E.A. Incorporated introduces a digital interface that controls FCCU (Fluid Catalytic Cracking Unit) Slide Valve Actuator (including Plug, Butterfly or other valve actuator) movements accurately based on a 4-20mA Control signal (or digital signal) and the actual position transmitted by a digital transducer. 

The digital controller and transducer are offered with redundancy.  In the event of a digital component failure of the primary system, the system will switch automatically to the secondary or redundant system. 

Result: 100% reliability.

The controller may also be mounted or controlled via serial communication such as Ethernet or other communication protocol.  Integral parts of the system are the following screens:

Valve Footprint Screen

A footprint is taken of the valve actuator at the valve manufacturer's facility to serve as a baseline.  Another valve footprint is taken after installation but before start-up (nearly one-third of installations are done incorrectly due to stress on valves).  Still another footprint is taken at the beginning of the operation.  This is the all-important baseline against which all future baselines will be measured.  Baseline trends, when compared to test trend, will show if the valve is beginning to fail in time to take preventative action.

Options

A strain gauge can be supplied on the valve packing. A trend can be seen and will recognize the packing failure.  Also, a flow transducer may be integrated to measure the air or nitrogen used for packing purge. A thermal couple is mounted on the valve to measure temperature.  This is on the external walls and indicates if a hot spot occurs.  All of the above are shown as a trend.  A gradual trend indicates a potential failure is going to happen in the near future.  A sudden change in the data means the possibility of something failing in the process line and jamming the valve or the valve stem is damaged.  Knowing the time of the event and break makes it easier to identify the problem.

540 Series Digital Controller Main Screen Description

The main screen is the default screen during power-up. On this screen the user will be able to access all other screens.  This screen features two large dedicated displays.  The position display will always indicate valve positions as a percentage, 100% being fully open.  The other dedicated display is deviation.  Deviation is the percentage of error between command signal and actual position.  Under normal conditions this displays reads 0%.

There is an indicator next to alarms to indicate status. A green lamp indicates that the alarm is normal.  A red lamp indicates that there is a fault. 

• The 540 Series Digital Controller Main Screen is equipped with six critical alarms.
  • The first three alarms are electrical, hydraulic and maintenance. Should a fault occur, the operator of the controller should press the button next to the indicator to go to a screen which details the alarm.
  • The next alarm is the auto alarm, which indicates the status of automatic operation. Under normal conditions the system should always be in auto. However, should this occur, the system may be set to auto again by pressing the button next to the auto alarm indicator.
  • The next two alarms are CPU1 & sensor. These two alarms monitor the controller and the position sensor. Should there be a fault with either alarm, the indicator will turn red.

Other 540 Series Digital Controller Screens:

• Digital Position Transducer Information Screen - Provides 8 digital string for controller positioning.  No drift at any time.
• Calibration Screen - Allows the user to configure new actuator stroke information via push-button entry without valve movement.  The redundant digital control can be calibrated on-line.
• Maintenance Manger Screen - Assists the user in maintaining hydraulic equipment by recording all filter changes, oil changes, temperature variations and shutdown required maintenance.  These items will automatically pop-up on the screens as they become necessary.
• Electrical Alarm Screen - Monitors all electrical data such as input feedback, tracking, power supply levels, limit switches, thrust, controller and hand wheel use.
• Hydraulic Alarm Screen - Monitors all hydraulic data such as ESD operate, ESD test, ESD active, lock in place active oil level and oil temperature.
• Trouble Shooting Screen - Assists the user to resolve problems with the slide valve actuator by showing problems and cause scenarios.
• Motor Control Screen - Allows the user to control the automatic switch-over between electric or pneumatic motors. Also allows the motor to be used manually to select primary motor and secondary motor and automatically select the time interval between motor cycles.
• Thrust Indication Screen - Allows the user to monitor the thrust in each direction exhibited by the actuator.
• Transmitter Data Screen - Allows the user to see all transmitter values and change the alarm set points, if desired.
• Alarm History Screen - Allows the user to view past hydraulic or electrical alarms while time stamping of all events.
• Trend Screen - Allows the user to view actuator position, control signal and pressure transmitter information for the past 24 hours for trouble-shooting purposes.  

Typical Specifications: