ISA CCST Level II case studies
ISA CCST Level II · Put your knowledge to work in context.
The ISA Certified Control Systems Technician (CCST) Specialist - Level 2 is the middle of three CCST certification levels offered by the International Society of Automation for control systems technicians. ISA describes Level 2 as demonstrating Level 1 knowledge plus some knowledge of administration, supervision or management, and it carries a seven-year minimum education and experience requirement. The ISA CCST Level II case studies are 5 cases and about 3,052 words.
1Zero Trim on a DP Flow Transmitter After a Range Change
A natural-gas flow loop uses a smart DP transmitter on an orifice plate. The transmitter is ranged 0–40 inH2O = 0–12 MMSCFD, 4–20 mA, powered from a 24 VDC loop with a 250 Ω sense resistor into a DCS analog input.
662 words, about 3 min2Control Valve Stiction and Low Air Supply on a Temperature Loop
A temperature control loop on a shell-and-tube exchanger controls product outlet at 120 °C by modulating a 4-inch pneumatic globe valve with a digital positioner. The controller output is 4–20 mA; the valve has spring-return fail-closed action and a 0–100% position feedback signal to the DCS.
608 words, about 3 min3DCS Scaling and Alarm Error Found During a Level Loop Check
A new tank farm has 22 guided-wave radar level loops wired to a DCS. The loop-check procedure requires injecting 4, 12, and 20 mA at the transmitter terminals and verifying the DCS indication and alarms.
579 words, about 3 min4Field Verification Versus Schedule Pressure on a PLC Replacement
A 10-week project replaces three legacy PLC-5 panels with a new control system: 180 discrete and analog I/O, four vendor skids, and a SCADA historian. The engineering firm issued drawings marked “Issued for Construction” based on P&IDs that are 12 years old and carry hand-drawn field changes.
604 words, about 3 min5Overdue Safety-Critical Calibrations and Falsified Work Orders
You supervise eight instrument technicians at a chemical plant. An internal audit finds that 12 of 60 safety-critical instrument calibrations are overdue by 30 to 75 days.
599 words, about 3 min