TTR 101 Vacuum Gauge Troubleshooting Guide

Leybold THERMOVAC TTR 101 Vacuum Transmitter: A Complete Guide to Selection, Installation, Debugging, and Troubleshooting

Introduction: When your vacuum measurement requires high precision and wide range

Accurate measurement of vacuum pressure is the core of process control in semiconductor, coating, freeze-drying, analytical instruments, and research laboratories. The traditional Pirani vacuum gauge performs well in the low vacuum range (<1 mbar), but lacks accuracy near atmospheric pressure; Although capacitive thin film vacuum gauges have high accuracy and are independent of gas types, their measurement range is limited and the cost is high. Leybold's THERMOVAC TTR 101 series integrates Pirani sensors and capacitive thin-film sensors into the same transmitter, achieving wide range and high-precision measurements from 5 × 10 ⁻⁵ mbar to 1500 mbar. It meets the digital requirements of modern vacuum systems through logarithmic voltage output (0-10.23 V) and optional switch output (SP1, SP2) or Profibus interface.

This article is based on the TTR 101 series operation manual, providing a detailed technical guide from product selection, technical specifications, installation wiring, gas type correction, set point adjustment, troubleshooting to maintenance and calibration, to help engineers quickly master the use and replacement of the transmitter.

Overview and Selection of Product Series

The TTR 101 series includes three sub models to meet different application requirements:

Model Part Number Example Switch Function Interface Display

TTR 101 230 350 V01 (KF16)/230 351 V01 (NPT) No analog quantity+optional identification resistor (with display version suffix)

TTR 101 S2 230 352 V01 (KF16)/230 353 V01 (NPT) 2-channel solid-state relay analog+identification resistor+switch output optional

TTR 101 PB 230 358 V01 (KF16) 2-channel (via Profibus) Profibus DP no display (via bus communication)

All models use a combination sensor (Pirani+capacitive film) with a measurement range of 5 × 10 ⁻⁵~1500 mbar. Vacuum connection options include DN 16 ISO-KF (quick release flange) or ⅛ "NPT thread.

Selection suggestion:

Only analog output is required (such as connecting to Graphix, Display, or Center controllers), select TTR 101.

On site switch control is required (such as interlocking and alarm), choose TTR 101 S2.

Need to connect to Profibus DP network, select TTR 101 PB.

Core technical parameters and accuracy

2.1 Measurement principle and scope

There are two sensors inside TTR 101 that always work:

Diaphragm capacitive sensor: covering 10~1500 mbar, independent of gas type, with high accuracy.

Pirani sensor (thermal conductivity type): covers 5 × 10 ⁻⁵~1 mbar, and needs to be adjusted according to changes in gas type.

Crossover range: 1~10 mbar, two signals are fused proportionally.

2.2 Accuracy (N ₂ calibration)

Pressure range accuracy

5 × 10 ⁻⁴~1 × 10 ⁻³ mbar ± 50% reading

1 × 10 ⁻ ³~100 mbar ± 15% reading

100~950 mbar ± 5% reading

950~1050 mbar ± 2.5% reading

Note: The accuracy is lower in the Pirani lower limit region (<10 ⁻ ³ mbar), but this region is usually used to determine rough vacuum or extreme vacuum, and the absolute error is acceptable.

2.3 Repeatability

The repeatability of readings is ± 2% within the range of 1 × 10 ⁻ ³ to 1100 mbar.

2.4 Output signal

Voltage range: 0~+10.23 V

Measurement signal range:+0.61~+10.23 V (corresponding to pressure 5 × 10 ⁻⁵~1500 mbar)

Fault signal: 0 V (default)

Voltage pressure relationship: logarithmic characteristic, 1.286 V/decade

Output impedance: 2 × 4.7 Ω, short circuit protection

Load impedance:>10 k Ω

Response time:<30 ms

2.5 Power Supply and Power Consumption

Supply voltage: 14.5~30 V DC (recommended 24 V DC)

Maximum power consumption: ≤ 2 W

Has reverse polarity protection

2.6 Switching output (S2 and PB models only)

Type: Solid state relay (optocoupler)

Setting range: 5 × 10 ⁻⁵~1500 mbar

Delay: Threshold 10% (programmable)

Switch characteristics: Low Trip Point (default) or High Trip Point (default)

Contact capacity:<30 V AC/DC, ≤ 0.3 A resistive load

Response time:<30 ms

2.7 Environment and Machinery

Working temperature:+5~+60 ° C (with display version up to 50 ° C)

Storage temperature: -40~+70 ° C

Baking temperature: up to 120 ° C (only sensor part, electronic unit needs to be removed)

Protection level: IP40 (after installation)

Shell material: stainless steel sensor+plastic electronic unit

Weight: Approximately 200 grams

Installation and mechanical connection

3.1 Installation direction and position

The transmitter can be installed in any direction. To prevent condensation and particles from entering the measurement chamber, it is recommended to adopt a horizontal to vertical upward installation posture.

If using seals with centering rings and filters, ensure that the filter mesh is clean.

After installation, the buttons (used to adjust zero/atmospheric pressure and set point) should be accessible, so there should be reserved operating space.

3.2 Grounding and Electromagnetic Compatibility

Key requirements:

The transmitter must be reliably grounded through a vacuum chamber (in accordance with EN 61010 protective grounding requirements).