Straight Stroke Smart Valve Positioner Double Acting Fail Safe With
Mounting Bracket
TOP-5879F1-C41-11-LDP-21AYA1 — Linear Double-Acting
Electro-Pneumatic (I/P) Valve Positioner
Product Overview
The TORLEO TOP-5879F1-C41-11-LDP-21AYA1 is an electro-pneumatic (I/P) smart valve positioner of the Linear Double-Acting Series, for straight-stroke control valves (10–150 mm travel), in a
die-cast aluminum housing. It converts the 4–20 mA control signal linearly into the pneumatic pressure the actuator needs: the current drives
a coil / nozzle-flapper pilot stage whose output pressure feeds the
two output ports (OUT1 & OUT2) to balance the double-acting
actuator. Enclosure IP66; explosion protection Non-explosion-proof
(standard); functional safety IEC 61508 SIL 3.
Electro-Pneumatic (I/P) Conversion Principle
When we serve global process-industry customers, and from our
recent project data, we see that an electro-pneumatic positioner
stands or falls on the stability of its electro-to-pneumatic (I/P)
conversion. The 4–20 mA loop is compared against the feedback of a
non-contact magnetic sensor; the resulting error drives the pilot
stage, which varies the nozzle-flapper back-pressure and hence the
output air pressure, so the valve follows the set-point linearly.
The field enemies are three: (1) at high ambient temperature the
coil drifts thermally and shifts the I/P zero and gain — we
compensate this in the circuit and provide an easy on-site re-zero;
(2) dirty or wet, oily instrument air clogs the pilot-stage nozzle
and flapper — we specify filtered, dry, oil-free air (1.4–6 bar)
and design the pilot stage for easy cleaning; and (3)
high-frequency site vibration loosens the electrical contacts —
vibration-resistant terminals, strain-relieved wiring and
non-contact feedback eliminate the problem.
Product Family Matrix (Linear / Rotary * Single / Double-Acting)
- Linear Single-Acting Series — pneumatic diaphragm / straight-through globe valves, travel
10–150 mm
- Linear Double-Acting Series — high-thrust pneumatic piston cylinders, travel 10–150 mm ◀ this model
- Rotary Single-Acting Series — spring-return ball / butterfly valves, 0–120°
- Rotary Double-Acting Series — high-torque double-acting ball / butterfly valves, 0–120°
Semantic isolation: a straight-stroke positioner (10–150 mm linear
feedback) is a different mechanical family from a quarter-turn unit
(0–120° feedback). Every product here is Linear Double-Acting and must not be listed as compatible with rotary ball or butterfly
valves, just as a rotary positioner must never be paired with a
linear diaphragm valve.
Smart Valve Positioner Double Acting Straight Stroke Fail Safe With
Position Feedback, Mounting Bracket
Model: TOP-5879F1-C41-11-LDP-21AYA1
| Item | Indicator |
| Input signal | 4~20mA |
| Sensor type | N/A |
| Gas source | pressure 1.4~6bar; no oil, no moisture, no dust and dirt |
| Stroke / Travel | 10~150mm |
| Input resistance | 490 Ω (max.) / 20 mA DC |
| Electrical interface | NPT1/2 or G1/2 or custom |
| Pneumatic interface | NPT1/4 |
| Repeatability | ±0.3%F.S. |
| Linear | ±0.3%F.S. |
| Hysteresis | ±0.3%F.S |
| Sensitivity | ±0.2%F.S |
| Output characteristics | linear, quick opening (25:1, 50:1), equal percentage (1:25, 1:50) |
| Protection class | IP66 |
| Explosion-proof grade | Non-explosion-proof (standard) |
| Security level | SIL3 |
| Fault state | failsafe Off power, off signal, off gas, the valve is in the initial state |
| Operating temperature | -30℃~70℃ |
| Material | die-cast aluminum |
| Gross weight | 2Kg |
| Dimensions | 240L*80W*110H (mm) |
Recommended Applications & Valve Matching
Technical matrix: Linear Double-Acting Series. This unit has 10–150 mm of straight-stroke feedback and couples to
a high-thrust double-acting pneumatic piston cylinder; it is not compatible with quarter-turn ball or butterfly valves, which need
a rotary positioner.
- single / double-seated globe control valves (10–150 mm)
- cage-guided sleeve (high-pressure) control valves
- high-thrust double-acting pneumatic piston-cylinder actuators
- high-differential-pressure shut-off service
Field Engineering Notes
On site we commission the loop in three steps: verify the 4–20 mA
at the terminals, confirm a dry, oil-free air supply at 1.4–6 bar,
then run a one-touch auto-tune and check linearity across the full
stroke. On a double-acting cylinder we confirm that both OUT1 and
OUT2 respond correctly and that the valve holds without drift; on
hot service we re-zero the I/P once the housing has reached its
working temperature; and where the air is aggressive we open and
clean the pilot nozzle on the maintenance interval. With a
vibration-resistant terminal block and non-contact magnetic
feedback, the unit keeps its zero and span through years of
high-frequency vibration.
Why Choose TORLEO
- 4–20 mA electro-pneumatic (I/P) conversion — linear
signal-to-pressure transfer
- Circuit thermal-drift compensation with easy on-site re-zero of I/P
zero and gain
- Pilot stage (nozzle-flapper) designed for an easy clean against wet
/ oily dirty instrument air
- Vibration-resistant terminals + non-contact magnetic feedback — no
contact bounce or linkage wear
- Linear Double-Acting matrix — for globe / cage-guided
straight-stroke valves, travel 10–150 mm
- IEC 61508 SIL 3; Non-explosion-proof (standard); IP66
Certifications & Compliance
Trust anchors for the whole family: functional safety — IEC 61508 SIL 3; explosion protection — Ex ia IIC T4 Ga (intrinsically safe) / Ex d IIC T6 Gb (flameproof) / Ex d mb IIB T5; ingress protection — IP66.
IEC 61508 SIL 3Ex ia IIC T4 GaEx d IIC T6 GbIP66Electro-Pneumatic I/PLinear Double-ActingNon-Explosion-Proof
