PIE 311 / 311Plus Automated Universal RTD Calibrator

Handheld universal RTD calibrator family with patented wire detection; 311Plus adds a full diagnostic milliamp calibrator (source/read/simulate/power + ground-leak detection).

Key advantages

12 RTD types — Pt 10/50/100/200/500/1000 (α=3850), Pt100 α=3902/3916/3926, Cu 10/50, Ni 120; ohms to 4010 Ω.
±(0.015% of reading + 0.05 Ω) — RTD/ohms accuracy class (311Plus datasheet).
Patented RTD wire detection — automatic 2/3/4-wire sense; find open leads.
311Plus milliamp side — 0…24.000 mA source/read; 2-wire simulate; 24 V power & measure; 250 Ω HART; patented ground-leak detection.

Typical applications

Calibrating RTD transmitters, PLC/DCS inputs, and recorders in °C/°F.
311Plus: combined RTD + 4–20 mA loop checkout and leak diagnosis.
Field/shop work with EZ-DIAL / EZ-CHECK stepping.

Selection guide

311 vs 311Plus — Both RTD/ohms; 311Plus adds full mA diagnostic calibrator.
RTD accuracy — ±(0.015% of reading + 0.05 Ω); resistance 0…401 / 0…4010 Ω.
mA (311Plus) — ±(0.02% of reading + 0.003 mA); compliance ≥24 V @ 20 mA; ~1200 Ω drive.
Environment — Operating −25…60 °C; four AA batteries; boot included on typical kits.
Stepping — Auto steps 2/3/5/11/21; step times 5…60 s.

Common mistakes

Ordering 311 when milliamp diagnostics of 311Plus are required.
Ignoring pulsed-excitation compatibility on multichannel instruments — PIE emphasizes broad compatibility, but confirm duty.
Forgetting HART 250 Ω need — built into 311Plus.
Calibration

When to RFQ / what to tell us

311 vs 311Plus.
RTD types and 2/3/4-wire duties; mA/HART needs.
Accessories (boot, leads, NiMH kit); quantity; ship-to.

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Specs

Spec	Value
SKU	32262
Brand	PIE (Practical Instrument Electronics)
Model	311 / 311Plus
Product type	universal RTD calibrator (311Plus: RTD + diagnostic mA)
Accuracy	RTD/ohms ±(0.015% of reading + 0.05 Ω); mA (311Plus) ±(0.02% of reading + 0.003 mA)
Supply voltage	Four AA alkaline (NiMH kit optional)
Notes	Specs from piecal.com 311 / 311Plus pages and 311Plus datasheet.

Documents

FAQ

Q: Do I need 311Plus? A: Choose 311Plus when you also need source/read/simulate mA, 24 V power & measure, HART 250 Ω, or ground-leak detection.

Q: What should I send for a quote? A: 311 vs 311Plus, RTD types, mA needs, accessories, quantity. Compatible with systems using PIE 311/311Plus if you need a drop-in check — we do not claim authorized-dealer status.