IMI STI QuickTrak TM Digital Valve Control System

QuickTrak TM digital valve control system for fast, accurate actuator positioning

The IMI STI QuickTrak TM is a digital valve control system that combines a microprocessor controller, a stepper-driven servo-valve and a magnetostrictive position probe into one package for a pneumatic actuator. Unlike a conventional positioner that bleeds a small pilot stream, it moves a high-flow spool directly, which lets it stroke large actuators quickly without a separate volume booster. Seven Star LLC supplies QuickTrak TM systems in Oman and the GCC as an independent supplier in Muscat.

The family is built around a DPS (Digital Position System) architecture with three main assemblies: the servo-valve (available as a Cv 30 or Cv 9 model), the digital controller with its display and power supply, and the feedback probe fitted inside the actuator. Because these are separate assemblies, the controller can be mounted on the actuator or remotely in a milder, safer location.

Technical specifications of the QuickTrak TM

Certification depends on the version ordered, as the model selection sheet separates ordinary and hazardous housings and the certification label. Confirm the marking against your area classification before purchase.

How the QuickTrak TM controls a valve

The digital controller compares the 4-20 mA command with the true stem position measured by the magnetostrictive probe, and with the position of the servo-valve spool. Based on both errors it drives the stepper motor, which shifts the spool and changes the air pressure above and below the actuator piston. Three pressure transducers inside the servo-valve manifold measure supply pressure and both cylinder chambers, giving the controller a pressure picture as well as a position picture.

The manufacturer highlights a resolution better than 0.25 % of stroke in its brochure, compared with about 1 % for conventional systems, and a spool piece it says delivers a Cv many times higher than traditional smart positioners. In practice that means fast stroking, little overshoot and the ability to follow small signal steps. Because the flow capacity is high, the brochure notes that volume boosters are no longer required, which removes components from the actuator and reduces potential leak and failure points.

Fail modes and safety functions of the QuickTrak TM

Fail action is handled by pneumatic valves piloted from a continuously energised, normally closed 24 VDC solenoid valve. If power, signal or air is lost, or if the controller trips, the solenoid de-energises and the fail module drives the actuator to the configured state. Standard fail modules exist for fail-open, fail-closed and fail-in-place. The manual describes separate configuration pages for position-excess, power, signal and pressure failure, so each condition can be given its own response. The 3-way fail valves are described as SIL certified, and a third valve removes any air bleed once fail mode has occurred.

QuickTrak TM controller, display and data logging

Calibration, manual control and HART parameter setting are done through a push-button display on the controller, or from a PC with the manufacturer software over RS232 or a HART modem. When an SD card is inserted, the controller automatically creates a folder per month and stores two kinds of files: a periodic history file and event files. Event files are triggered by signal below minimum or above maximum, position error or warning, probe error and trips, and they capture a 20-second snapshot at 100 Hz sampling with a user-set pre-trigger time. This turns every upset into a diagnostic record without a laptop on site. The manual specifies a FAT 16 card of up to 2 GB.

Where the QuickTrak TM fits and related IMI STI parts

The QuickTrak TM is aimed at large or fast linear actuators, which is why the Cv 30 version uses a special actuator with enlarged end-plate ports and the Cv 9 version a standard IMI STI actuator modified to accept the probe, with a gun-drilled shaft. For smaller or less demanding loops IMI STI offers the DigitalTrak DT, a loop-powered compact positioner, along with the FasTrak and SHP smart positioners and the SA/CL analog positioner. Where a plant already has a QuickTrak of an older generation, note that the model selection sheet marks version II as obsolete and identifies version III as current, so state the generation when you request spares or a replacement.

Selection and ordering checklist for the QuickTrak TM

• Servo-valve size: Cv 30 for large, fast actuators; Cv 9 for medium sizes.
• Housing: ordinary or hazardous (Ex d), or special with a drawing.
• Certification label: UL, CSA, European CE/ATEX/IECEx, Customs Union, or no label.
• Display board type: complete, simplified or simplified with 24 V.
• Supply: 120 VAC, 240 VAC, 24 VDC, 48 VDC, 110 VDC or special.
• Terminal board for ordinary or hazardous location.
• Fail action required: open, closed or in place.
• Remote or actuator mounting, and cable length of the umbilical.

These headings follow the manufacturer model selection sheet, which uses a coded string with a Quick Trak model letter, version, housing, certification, display board, driver, supply and terminal board. Ordering from a code requires the exact combination, so send the existing nameplate if you are matching an installed unit.

Installation, commissioning and maintenance

Install on an actuator that has been specified and built for the DPS interface, with a clean, dry air supply whose dew point is at least 10°C below the lowest ambient temperature and a 5 micron filter regulator. The controller needs a ground connection and a supply protected against overcurrent, and the pressure transducers must remain correctly fixed inside the enclosure. After mechanical and electrical installation, enter the probe constant printed on the probe and run the self-calibration routine. The manual warns that the controller will move the cylinder through its range, including fully open and fully closed, so coordinate with operations first.

Routine maintenance is limited: clean with a damp cloth, keep the air system drained, and periodically download the SD card history to review trends. Use greases and oils according to the manufacturer instructions with a flash point above 140°C.

Typical QuickTrak TM applications in Oman and the GCC

Large pneumatic control and safety valves are common in oil and gas production, gas processing, power generation and desalination plants. The QuickTrak TM suits turbine control and bypass valves, large anti-surge or pressure-control valves and other duties where speed and load-step precision matter. In Gulf conditions, strong solar heating can push enclosure temperatures high, so remote mounting of the controller in a shaded or cabinet location is a sensible option, and dust-tight IP66 construction suits sandy sites.

Information to send with a QuickTrak TM request

• Part name QuickTrak TM, version and quantity.
• Existing nameplate or model code if replacing a unit.
• Actuator make, cylinder diameter, stroke and air supply pressure.
• Required fail action and any partial or full signal-fail behavior.
• Mounting: on actuator or remote, with cable length.
• Power source and hazardous area classification.
• HART or PC software requirements.

Documents and quotation

The manufacturer instruction manual for the QuickTrak TM (document 4039, general description and software) is attached on this page, covering the architecture, calibration, fail modes and SD card functions summarised above.

Send the part number, version and operating data to Seven Star LLC and we will confirm lead time and any additional documents, including the model selection sheet, for your QuickTrak TM configuration.