SRD998 Intelligent Positioner: Practical Guide for Commissioning, HART & Maintenance
Control valves are only as stable as the positioner driving them. The SRD998 Intelligent Positioner is designed to deliver consistent valve positioning, reliable response, and practical diagnostics to help technicians and engineers maintain control accuracy over time.
Whether you’re installing a new unit, recommissioning after shutdown, or troubleshooting an unstable loop, the SRD998 is typically approached with the same goals:
-
Accurate positioning for stable process control
-
Faster commissioning using setup features like Autostart/self-calibration
-
Better fault finding through diagnostic feedback
-
Reliable integration through common control and maintenance workflows (including HART on 4–20 mA loops)
This guide focuses on what matters most in the field: moving the SRD998 between actuators, connecting it via HART, fixing common Autostart failures, and setting up routine checks that prevent repeat problems.
What should you do before moving an SRD998 from one actuator to another?
If you move the positioner onto a different actuator/valve, treat it as a recommissioning job.
Best practice:
-
Confirm actuator type and travel requirements
-
Re-check linkage/feedback alignment
-
Re-run setup and calibration (Autostart) so the positioner learns the new mechanics
Skipping this is one of the fastest ways to end up with poor accuracy, unstable control, or repeated calibration faults.
Connecting SRD998 to HART
How do you connect SRD998 to HART?
HART connection is usually straightforward when the basics are right. The SRD998 typically runs on a 4–20 mA loop and can be configured via a communicator or compatible tooling used in maintenance/asset management workflows.
Quick checklist to avoid “device not found”:
-
Confirm you’re on the correct 4–20 mA loop wiring
-
Ensure the connection method follows your plant standard for HART access
-
Verify the loop is healthy and stable (many “HART issues” are actually loop/wiring issues)
KV Controls advantage: we can guide the best route for your team—local setup vs communicator vs maintenance workflow—so commissioning is faster and repeatable.
SRD998 Autostart Fails—Top Causes & Fixes
Autostart fails—what are the most common reasons?
Most Autostart failures come from mechanical, pneumatic, or mismatch issues.
Common causes (and fixes):
-
Incorrect mounting selection or feedback/linkage problems
Fix: verify mounting type (linear/rotary), linkage alignment, and feedback movement—then rerun Autostart. -
Air leaks, restrictions, or unstable supply air
Fix: leak check, confirm correct ports/routing, confirm air quality and stable supply. -
Actuator travel mismatch or mechanical binding
Fix: confirm valve travel range, actuator sizing, and free movement through the full stroke.
If a positioner is commissioned correctly, it typically remains stable—so the goal is to eliminate root causes during installation rather than chasing symptoms later.
Routine Checks That Prevent SRD998 Problems
What routine checks prevent SRD998 issues?
A simple routine prevents most long-term performance problems:
-
Maintain clean, dry instrument air (filters/regulators matter)
-
Perform periodic leak checks (small leaks become unstable control)
-
Visual inspection of mounting, fittings, and seals after shutdowns
-
Use diagnostics proactively during planned maintenance—don’t wait for failure
This approach reduces emergency callouts and improves valve loop stability across the plant.
KV Controls Supply & Support
If you’re planning upgrades, replacements, or standardisation, KV Controls can help you select the correct SRD998 configuration, ensure the right hazardous approvals where required, and support smoother commissioning so your valve control performs as intended.
FAQ
Q1: What does KV Controls supply for the SRD998 Positioner?
KV Controls supplies the SRD998 Intelligent Positioner as a complete valve positioner solution, including the correct model selection for your valve/actuator setup, plus practical commissioning guidance and dependable local supply.
Q2: Why do industries in South Africa choose the SRD998 Positioner from KV Controls?
Because the SRD998 delivers accurate valve positioning, faster setup (Autostart), and strong diagnostics—and KV Controls strengthens that value with support that helps plants reduce downtime, improve control stability, and keep critical valves performing reliably.
Q3: Which industries typically use the SRD998 Positioner supplied by KV Controls?
The SRD998 is commonly used in mining, petrochemical and oil & gas, energy and utilities, water and wastewater, and heavy manufacturing—anywhere stable control valve performance and reliable position feedback are essential.
Conclusion
The SRD998 performs best when commissioning is treated as a repeatable process: correct mounting, clean instrument air, stable loop conditions, and calibration that matches real travel. When issues occur, most can be traced back to mechanical alignment, pneumatic stability, or travel mismatch—meaning the fix is usually practical and systematic.
Partner with KV Controls in 2026
This year is about stability, efficiency, and fewer disruptions. With KV Controls, you gain more than equipment—you gain a trusted technical partner committed to helping your systems perform at their best, day after day.
