The Rotork YT3100RDI5111S is a configuration of the Rotork YTC YT-3100 compact smart positioner, designed to deliver accurate, repeatable valve positioning for industrial flow control. In plain terms: it takes a control system’s 4–20 mA command signal and turns it into stable pneumatic output to move an actuator so the valve actually lands where the process wants it. That sounds simple until you put it on a vibrating pipe rack, feed it imperfect instrument air, run it through thousands of cycles, and expect it to stay honest. The point of a smart positioner like this is to stay honest anyway.
The YT-3100 platform is built to serve both linear actuators and quarter-turn rotary actuators, and it supports single-acting and double-acting pneumatic arrangements. The specific unit code you provided, YT3100RDI5111S, indicates a rotary, double-acting, intrinsically safe build with NAMUR mounting and gauge block, plus an option for 4–20 mA position feedback. That makes it a practical choice for control valves in oil and gas, chemical processing, power and utilities, water treatment, and any plant where stable modulating control is more important than flashy features.
What makes this model worth caring about
A positioner is not just “an accessory on the side of the actuator.” It is the part that closes the loop between command and reality. A controller can output a perfect signal, and the valve can still drift, stick, overshoot, or hunt if the positioner is slow, unstable, or poorly matched. The YT-3100 design emphasizes compactness, usability, and diagnostic clarity. It uses a menu-driven interface with four push buttons for setup, and supports visual self-diagnostics aligned with NE107 conventions so maintenance teams get clearer fault meaning instead of cryptic behavior.
For applications that cycle frequently, the product literature highlights a non-contact sensor approach intended to support performance and service life under high-frequency valve operation. And for plants that care about “what did the valve actually do,” the YT3100RDI5111S configuration includes an option for 4–20 mA position feedback, which can be fed back into a DCS/PLC for monitoring, trending, and alarm logic.
Model code decoding for YT3100RDI5111S (so you know exactly what you’re buying)
One of the most useful parts of the YT-3100 documentation is that the code is not random; it’s a structured configuration string. Based on the published product code legend, your part breaks down like this:
| Code Segment | Meaning | What It Implies in Practice |
|---|---|---|
| YT-3100 | Base model | Compact smart positioner platform |
| R | Rotary | Intended for quarter-turn actuators |
| D | Double acting | Two pneumatic outputs to drive both directions |
| I | Intrinsically safe | Designed for hazardous area use under listed approvals |
| 5 | NAMUR | Standard rotary actuator mounting convention |
| 1 | G 1/2 conduit + Rc 1/4 air | Common industrial threading for wiring/air connections |
| 1 | Gauges block included | Local pressure indication and easier on-site checks |
| 1 | PTM 4–20 mA feedback option | Position feedback signal available to control system |
| S | -30 to +85 °C operating range | Wide ambient range for demanding environments |
This decoding matters because “YT-3100” alone is not a full purchase definition. The suffix tells you whether it’s rotary vs linear, single vs double acting, safe area vs hazardous area, and which mounting and connection standards it matches.
Key Technical Specifications (from published YT-3100 data)
The following parameters reflect the YT-3100 specification sheet for the YT-3100 family.
| Specification Item | Value |
|---|---|
| Input signal | 4 to 20 mA DC |
| Supply pressure | 0.14 to 0.7 MPa (1.4 to 7 bar / 20 to 102 psi) |
| Stroke range (rotary) | 55 to 110° |
| Stroke range (linear, for reference) | 10 to 150 mm |
| Max impedance | 500 Ω at 20 mA |
| Air connection | Rc 1/4 or 1/4 NPT (depends on option) |
| Gauge connection | Rc 1/8 or 1/8 NPT |
| Conduit | G 1/2 |
| Operating temperature | -30 to +85 °C (-22 to +185 °F) |
| Accuracy terms | Linearity ±0.5% F.S.; Hysteresis ±0.5% F.S.; Sensitivity ±0.2% F.S.; Repeatability ±0.3% F.S. |
| Air consumption | Below 2 LPM at 0.14 MPa supply |
| Flow capacity | 70 LPM at 0.14 MPa supply |
| Output characteristics | Linear, equal percentage, quick open, user set |
| Housing / cover material | Aluminium diecasting housing, polycarbonate cover |
| Ingress protection | IP66 |
| Weight | 1.7 kg (3.7 lb) |
| Hazardous area notes (family) | ATEX / IECEx / CCC mentioned; intrinsic safety classifications listed in datasheet |
Where YT3100RDI5111S fits best in a plant
1) Modulating control valves that need stable positioning
If your loop is fighting oscillation or deadband, the positioner is often where the battle is won or lost. The YT-3100 family’s published performance metrics (linearity, hysteresis, repeatability) are aimed at predictable behavior across the stroke.
2) Rotary actuators with NAMUR mounting
The “R…5…” segments indicate rotary motion and NAMUR mounting, which is common across many actuator brands and makes installation cleaner and more standardized.
3) Hazardous-area capable installations
The “I” segment indicates an intrinsically safe variant, and the datasheet lists multiple hazardous-area approval families and intrinsic safety markings for the product line. This is especially relevant in refineries, chemical plants, and gas handling areas where safe-area-only hardware becomes a procurement trap.
4) Applications where feedback is valuable
The “options = 1” in the product code corresponds to a PTM 4–20 mA feedback option. That’s useful for valve travel monitoring, proof-of-movement logic, and maintenance analytics (for example, spotting a valve that is being driven hard just to achieve modest flow change).
Commissioning and maintenance mindset
The YT-3100 is positioned as a compact smart unit with a straightforward menu and push-button navigation. In practice, that means fewer excuses for leaving a valve “close enough” during startup. It also means a maintenance tech can walk up, check gauge pressures (on the gauge-block version), verify response, and interpret diagnostic status faster. Over time, those minutes saved become fewer production disruptions and fewer midnight call-outs.
Summary
Rotork YT3100RDI5111S is not a generic “YT-3100.” It is a very specific build: rotary + double acting + intrinsically safe + NAMUR + gauge block + 4–20 mA feedback option + wide temperature range. If you need a compact smart valve positioner that plays nicely with standard industrial instrument air and a 4–20 mA control loop, and you want the configuration to match real installation conventions rather than “close enough,” this code is engineered to be a clean fit.
