Diagnostic Versions (Hart and AS-Interface) – Axiom®

Diagnostic systems

Reduce plant downtime and cut maintenance costs

The Axiom AS-Interface and HART models feature on-board diagnostics that predict potential automated valve malfunctions. As a result, plant downtime may be reduced by repairing automated valves during planned shutdowns instead of process operations. Should problems occur during process operation, maintenance personnel will be aided by rapidly locating failure causes, consequently speeding up valve repair and operation renewal.

Identify potential problems

  • Check air supply pressure. Alerts are activated if low or high levels exceed preset thresholds that would threaten pneumatic valve or actuator performance.
  • Determine solenoid condition. Voltage and current levels are monitored to determine the health of the solenoid coil whenever energized.
  • Local trouble-shooting display. Device LED array identifies problem sources for rapid trouble-shooting and maintenance at the valve/actuator site.
  • Monitor pneumatic spool and pilot valve operation. Pneumatic valve spool position is monitored to determine proper shifting performance when the solenoid is energized and de-energized. 
  • Remote switch setting. Open and closed limit switch settings may be made with on-board push buttons or remotely through the control system. 
  • Field identify with “winking”. To positively confirm the field device identity, the control room may initiate the “wink” function that flashes both open and closed LEDs without affecting valve operation.
  • Stuck process valve/actuator. If the Axiom stalls in mid stroke and no Axiom problem sources are identified an alert will be energized to indicate the problem source is in the valve/actuator assembly. 

Axiom® with AS-Interface diagnostics (AMI96) for networking applications

The AMI96 offers basic diagnostics for AS-Interface network applications that enable end use customers to increase uptime and reduce maintenance costs. Axiom AS-Interface diagnostic systems interface with any version 2.1 or greater masters/gateways.

  • Electrical connections: The Axiom with AS-Interface diagnostics uses standard (1-31) addressing with a 4DI/4DO profile to maximize the diagnostic data available via the network. Diagnostic units may be integrated on the same network as other AS-Interface devices.
  • Control system interface: Interface up to 31 Axiom units into your control system. Communication bits may be mapped into standard DCS or PLC as desired. No special software is required. See the StoneL FieldLink program for information about the cost saving benefits and easy installation of the AS-Interface protocol.


Axiom® with HART (AMI71) features comprehensive predictive diagnostics

The AMI71 is a valve monitoring and control device for discrete quarter-turn automated valves. Used in conventional applications, it has the added capability of providing diagnostic information for the pilot solenoid, spool valve, and actuator. And, the device stores historical data on each open and closed operation. 

  • Excessive valve torque changes. Open and closed breakaway actuator differential pressures are measured and compared to baseline levels during each operation. This enables operators to observe unusual pressure/torque level trends, which may ultimately lead to a malfunction.
  • Erratic valve/actuator performance. Total travel time and dead time (time between energizing and initial actuator movement) are measured during each operation, recorded, and compared to the baseline. This gives maintenance staff additional clues on potential automated valve problems. 
  • Valve/actuator end-stop changes. Exact valve position is continuously measured and may be used to determine if changes have occurred at end-of-travel. Deviations from zero or span endpoints are graphically portrayed to alert maintenance staff of worn end-stops.

Easy control system integration

  • System connections: Two, 2-wire connections attach to the control system to provide discrete solenoid control and continuous position monitoring. A standard 24 VDC discrete output (DO) powers and controls the solenoid valve. Intrinsically safe solenoid pilot may also be selected. A conventional 4 to 20 mA analog input (AI) provides continuous exact valve position feedback into the control system.
  • Hart Signal: The HART communication signal is overlaid on the 4 to 20 mA analog position monitoring input. The signal may be read via internal modem in the DCS system or external modem. External modems may transmit information to a DCS or to a remote PC via a hardwired or a wireless connection.
  • Software integration: Integration to various DCS or asset management systems may be achieved using open, standardized technologies such as enhanced EDDL (Electronic Device Description Language) or FDT/DTM (Field Device Tool/Device Type Manager). Most DCS vendors use one or both of these technologies, which provides open access to device intelligence and allows easy use of all features and benefits available from the Axiom HART device Click here to download EDDL and DTM Files.