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YOKOGAWA SNT501-5F
Product Introduction:
The SNT501-5F is a smart temperature transmitter from Yokogawa’s SNT500/YTA710 series. It converts RTD (Pt100) temperature sensor signals into a standardized 4–20 mA DC output for transmission to DCS, PLC, or SCADA systems. The “5F” designation specifies Pt100 input with a temperature range of −200°C to +650°C.
Detailed content
Measurement Principle:
The transmitter accepts the resistance change of a Pt100 RTD element (100 Ω at 0°C, following the IEC 60751 standard curve). The internal microcontroller linearizes the resistance-to-temperature conversion using the Callendar-Van Dusen equation, applies cold junction compensation, and outputs a proportional 4–20 mA DC signal.
Technical Specifications:
| Parameter | Specification |
|---|---|
| Model | SNT501-5F |
| Input Sensor | Pt100 (IEC 60751, α = 0.00385) |
| Temperature Range (5F) | -200°C to +650°C (-328°F to +1202°F) |
| Output Signal | 4–20 mA DC (2-wire, loop-powered) |
| Accuracy | ±0.1% of span |
| Ambient Temperature Effect | ±0.05% of span per °C |
| Power Supply | 12–36 V DC (2-wire loop-powered) |
| Load Resistance | Up to 600 Ω (at 24 V DC supply) |
| Response Time | ≤ 1 second (τ63%) |
| Protection Class | IP65 (with cable gland) |
| Wetted Materials | SUS316L Stainless Steel |
| Process Connection | 1/2″ NPT, M20 × 1.5, or 3/4″ NPT (varies by configuration) |
| Communication | None (standalone 4–20 mA transmitter) |
| Approvals | CE, ATEX, IECEx, FM, CSA, SIL2 |
| Housing Material | Aluminum Die-Cast (painted) or SUS316L |
Structural Features:
- Head-mount or DIN rail-mount transmitter housing
- Screw-terminal connections — 3-wire or 4-wire RTD input
- IP65 rated — suitable for outdoor and washdown installations
- Large terminal compartment — easy wiring in the field
- Zero and span adjustment via front panel push buttons (with cover)
Performance Parameters:
| Parameter | Value |
|---|---|
| Input Type | 2-wire, 3-wire, or 4-wire Pt100 |
| Lead Wire Resistance | Up to 100 Ω (3-wire compensation) |
| Insulation Resistance | ≥ 100 MΩ at 500 V DC |
| Dielectric Strength | 1500 V AC, 1 minute (input to output to power) |
| Zero Drift | ±0.1% of span per year |
| Span Drift | ±0.1% of span per year |
| Operating Temperature | -40°C to +85°C (-40°F to +185°F) |
| Storage Temperature | -40°C to +85°C |
| Weight | Approx. 0.6 kg (with cable gland) |
Key Advantages:
- ±0.1% accuracy — high precision for process control
- Wide temperature range (−200°C to +650°C) — covers cryogenic to high-temperature applications
- 3-wire RTD input — compensates for lead wire resistance automatically
- IP65 rated — robust for field and outdoor installations
- SIL2 functional safety certified — suitable for safety instrumented functions
- Loop-powered (2-wire) — no separate power supply needed
Applicable Industries:
- Oil and Gas (Refineries, Pipelines)
- Chemical Processing
- Power Generation (Boilers, Turbines)
- Food and Beverage (Pasteurization, Sterilization)
- Pharmaceutical (Autoclaves, Freeze Dryers)
- Cryogenic Applications (LNG, Liquid Nitrogen)
- Metallurgy and Heat Treatment
Installation Requirements:
- Install the transmitter in a location accessible for maintenance
- Ensure the thermowell is fully immersed in the process fluid
- For 3-wire RTD: all three lead wires must be the same length and same gauge for accurate compensation
- Use shielded twisted-pair cable for the RTD connection
- Ground the transmitter housing to the plant ground system
- Install a cable gland (PG13.5 or PG21) for IP65 protection — do not leave the cable entry open
Usage Precautions:
- Never disconnect the RTD sensor while the transmitter is powered — this will cause an open-circuit alarm
- Verify the RTD type matches the transmitter configuration (5F = Pt100) — using Pt1000 will cause 10× error
- Do not exceed 36 V DC on the power supply
- Do not exceed the maximum process temperature (+650°C for 5F range)
- Periodically verify zero and span — recalibrate annually or per plant procedure
- Protect the cable gland threads — do not over-tighten; use PTFE tape
- Do not paint over the nameplate — it contains critical configuration information
