M.E.A. Incorporated 841 Series Digital Controller

M.E.A., Inc. introduces it's 3rd generation of Digital Controllers. The Model 841 Digital Controls can be easily adapted to any Slide Valve, Butterfly Valve, Plug Valve, or any other new or existing valve actuator. This allows economical conversion from analog to digital control, replacing obsolete analog parts. Conversion can be done on-line or during a turnaround. MEA Redundant Digital Controllers offer proven 100% reliability with units operating throughout the world since 2003. Redundant Controllers consist of 2 nodes. Each node can control the actuator independently of the other. Software on the controller will not only monitor valve position and alarms but will also monitor the status of the other node and the node's individual components. When a component or node failure is sensed the proper switchovers will occur to ensure the unit continues running without any interruption of service and without the necessity of human intervention.

SEE WHAT THE MEA DIGITAL CONTROLLER CAN DO FOR YOU....

Provides most accurate and stable control of any slide valve actuator.
Promises continuous performance; no electronic problems to shut you down.
No more unplanned shutdowns or process upsets to cost you money.
Meets all electrical codes: NEC, ATEX, CSA, IEC, FM and UL.

MEA QUALITY AND SERVICE

MEA delivers quality assurance. MEA has earned the coveted designation of ISO 9001:2008 Certified.

MEA provides complete field service support through a minimum of five full-time, highly-skilled, hydraulic and electrical technicians

ADVANTAGES OF MEA DIGITAL CONTROLS

Digital Precision - Digital Position Servo-Sensors, Controllers, and I/O give precise position to a resolution of 1/1000th of an inch. No drift.
Self Diagnostics - Indicators on screen and sent to the customers DCS via either customer contacts or Modbus communications will show any problems that have arisen with components of the system.
External Enclosure Access - All user interfaces to the system are available from an external port outside the enclosure.
Simple Calibration - Detailed documentation and digital readouts make calibration quick and easy.
Predictive Maintenance - Using Valve Trending and Footprint analysis, valve actuator problems that can cause shutdowns can be predicted and avoided.
Parameter Driven Alarm Set Points - Alarm trip points can be set by the user.
Noise Immunity - MEA Engineers carefully layout each panel to segregate AC and DC wires. This, plus proper grounding techniques help eliminate noise from the panel.
Expandability - I/O ports and channels can easily be added per the customers request.
Network Connectivity - The MEA Digital Control panel is fully networked and available for hookup to the customers DCS.
Security - Password protection is utilized to secure all areas of the system.
All Programming conforms to the IEC standard 61131-3.
Valve Monitoring
Precision Jogging
Transmitter Displays

MODEL 841 OPTIONS

Motor Control - This gives a dual motor system the ability to control motor starts and stops automatically and with no human intervention. Options are also available for external switches that will allow the operator to override the software control of the motors.
Maintenance Manager - This option gives the user the ability to control and maintain a schedule of maintenance tasks. Alarms will notify either the operator or control room when maintenance dates are reached.
Manual Jog - This provides the operator the ability to override the control room's input signal and manually jog the valve.
Centralized Control - In the typical Decentralized Control scheme, the control panel is at the Hydraulic Power Unit (HPU). MEA offers a Centralized option that mounts the control panel in a cabinet located in your environmentally stable Control Room. Communication lines are run out to the HPU to control the valve. (See the picture below of a Centralized installation)
Remote Monitoring - Additional HMI screens can be located anywhere in the plant and display the same information as the HMIs on the control panel.
Thrust Limiting for Plug Valves - The MEA Model 841 allows for on the fly recalibration of the Zero position as Plug valves heat up. This eliminates the need for operator intervention. Thrust Limiting also works in reverse when the vessel is cooling down.
Alarm History - Alarm history can be stored and reported on for a user specified level of retention.
Valve Trending - The system has the ability to store and report on pressure increases throughout the operating life of the valve. This is done by taking a footprint reading of pressure at various points along the total stroke of the valve. Periodic readings after operations have started can then give indications of possible FUTURE failures.

The Main Screen is the default screen that each HMI will display upon power-up. From this screen the user will be able to access all other screens including the Setup and Options screens. The 2 large dedicated displays are for Valve Position and Deviation. The Position display will always indicate valve position as a percentage of the total stroke of the valve. Generally 100% will indicate being fully open but this can be reversed if desired by the customer. Deviation is the percentage of error between the command signal and the actual position. Under normal conditions this will be 0%. Alarm indicators give the number of alarms that have arisen with each area of the system. That being Electrical, Hydraulic, and Valve. The user can then press the button for each of these to view the status of individual alarms within each area. The Node Status box gives Operational Status of each component of the redundant nodes. It also displays which Node (Primary or Secondary) is currently in control of the valve.