Successor model — supersedes WIKA S-3 absolute transmitter
Specifications
| Pressure type | Absolute |
|---|---|
| Output | 4-20 mA / 0-10 V |
| Electrical connection | M16 threaded |
| Mounting | External thread / EHEDG-certified |
| Process connection | G 1/4, NPT 1/4, G 1/2, NPT 1/2, M20 × 1.5 |
| Material | 316 stainless steel, Hastelloy optional |
| Application | Process industries |
| Pressure range | 0-1 to 0-1000 bar (0/0.5/1/1.6/2.5/4/6/10/16/25/40/60/100/160/250/400/600/1000 bar) |
| Accuracy | 0.5% FS |
| Operating temp. | -40 … +125 °C +180 °C with cooling element |
Description
WIKA IS-3 is an intrinsically-safe absolute pressure transmitter engineered for high-precision absolute pressure measurement in process industries. The all-welded 316L stainless construction eliminates internal fill fluid contact, preventing media migration; ATEX / IECEx certification permits direct installation in zones 0/1/2.
A high-stability silicon piezoresistive cell delivers <0.1% FS/year long-term zero drift, with standard 4-20 mA HART or 0-10 V analog output. Multiple G/NPT/M20 process connections cover diverse pipework requirements.
Applications
Chemical reactor absolute pressure control, petrochemical process line monitoring, pharmaceutical vacuum distillation, F&B CIP/SIP systems, semiconductor high-purity gas lines, and power generation boiler vacuum sensing.
Frequently Asked Questions
What is the core difference between the IS-3 and the S-3?
The IS-3 is the intrinsically-safe successor to the S-3, adding ATEX and IECEx certification for Zone 0/1/2 hazardous areas. Mechanically it uses an all-welded 316L stainless construction with no internal fill fluid, whereas the S-3 is an oil-filled design. Both share 0.5%FS accuracy, but the IS-3 covers a wider pressure span (0-1 to 0-1000 bar) and offers a 2-wire 4-20 mA HART option that the S-3 does not support.
What is the difference between intrinsic safety and explosion-proof?
Intrinsic safety (Ex i) limits circuit energy so that no fault condition can ignite a flammable gas; explosion-proof (Ex d) uses a heavy-walled enclosure to contain any internal explosion. The IS-3 is Ex i, suitable for gas Zones 0/1/2 and dust Zones 20/21/22. Ex d enclosures are bulky and demand more installation space, while Ex i wiring is lighter and is the mainstream choice for process instrumentation.
What error does 0.5% FS accuracy mean on a 0-1 bar range?
FS denotes full scale, so 0.5% × 1 bar equals ±5 mbar (±500 Pa) maximum error across the entire 0-1 bar range. At a 0.5 bar reading, the true value lies between 0.495 and 0.505 bar. Scaled to a 0-100 bar range the error becomes ±0.5 bar; on 0-1000 bar it grows to ±5 bar. Pick a range so the typical operating point sits at 50% to 80% of FS to minimise relative error.
Which media damage 316L diaphragms? Should I choose Hastelloy?
316L handles water, oils, moderate-strength acids and alkalis, steam, and compressed air. Avoid: concentrated hydrochloric acid (HCl), hot hydrofluoric acid (HF), sulphuric acid (H2SO4) above 80%, ferric chloride (FeCl3), chloride-rich hot aqueous solutions, and wet chlorine gas. Specify Hastelloy C-276 for these duties; strongly oxidising fluorine media require a tantalum (Ta) diaphragm. The WIKA IS-3 lists Hastelloy as a standard option.
With a cooling element at +180 °C media temperature, will long-term stability degrade?
A cooling element (radiator) drops the electronics' actual temperature below +85 °C and buffers thermal cycling. Long-term zero drift remains within 0.1% FS per year. Installation rules: mount the radiator vertically, route media flow downward, and avoid stagnation inside the radiator. Plan a field zero-point calibration every 12 months and a laboratory full-span calibration every 24 months.
What is the maximum transmission distance for a 4-20 mA HART signal?
With 24 V DC supply, shielded twisted pair of at least 0.5 mm² cross-section, and single-point grounding, a pure 4-20 mA loop runs reliably to 1500 m. When HART digital communication is overlaid, keep the cable below 1000 m for stable handheld reads. Lower-grade or unshielded cable should be capped at 500 m. On long runs, verify cable voltage drop does not pull the transmitter supply below 12 V.
Is the IS-3 suitable for food and pharma, or should I pick the SAN series?
The IS-3 carries EHEDG hygienic-design certification but lacks the 3-A mark, and its connections are mainly threaded or flanged. For dairy, beverage, and biopharmaceutical CIP/SIP duties, choose the WIKA SAN-3 hygienic series: flush diaphragm, 3-A 28-04 certification, and Tri-Clamp hygienic connections. The IS-3 is better suited to chemical, oil and gas, and semiconductor process industries. Both share the same core sensing technology and can be cross-checked in the WIKA online configurator.
