WPI200 Digital Pirani Vacuum Gauge with 5-Digit LED Display RS485 & Analog Output

Comprehensive guide to TXWPI200 Pirani Vacuum Gauge featuring specifications, operation instructions, RS485 communication protocol, and application scenarios for precise vacuum measurement.

TXWPI200 Pirani Vacuum Gauge Technical Manual

1. Product Overview

The TXWPI200 integrated display Pirani vacuum gauge offers:

5-digit LED display with selectable units (Pa, Torr, mBar)

Dual setpoint control relays

Analog voltage output (+2.286V~+10.0V)

RS485 Modbus-RTU communication

Smart button operation for calibration and configuration

2. Technical Specifications

3. Key Features

3.1 Gas Type Compensation
The gauge requires calibration factors for gases other than air/N₂ below 100Pa:

3.2 Setpoint Controls

Two independent setpoint relays (60VDC/0.5A)

Setpoint range: 5.0×10⁻⁵~9.9×10⁴ Pa

Hysteresis: 110% of set value

4. Connection Interface

D-Sub 9 Pinout:

PWR GND

Setpoint Out A

Setpoint Out B

Analog Output

RS485 D-(B)

PWR +24VDC

Setpoint COM

Analog GND

RS485 D+(A)

5. Operation Guide

5.1 Front Panel Controls

3-button interface for:

Atmospheric pressure calibration

Zero calibration

Setpoint adjustment

Unit selection (Pa/Torr/mBar)

Display format (scientific/floating)

RS485 address configuration

Factory reset

5.2 Analog Output Modes
Two selectable voltage ranges with different calculation formulas:

+2.5V~+8.5VDC:
P = 10^(U-C)
Where C = 3.5 (Pa), 5.5 (mBar), 5.625 (Torr)

+2.286V~+10.0VDC:
P = 10^((U-c)/1.286)
Where c = 3.572 (Pa), 6.143 (mBar), 6.304 (Torr)

6. Communication Protocols

6.1 RS485 Modbus-RTU

Baud rate: 9600

Data bits: 8

Stop bits: 1

Parity: None

Register Address Table:

7. Application Scenarios

7.1 PLC Integration

Connect via RS485 to industrial PLC systems

Supports standard Modbus protocol

7.2 Computer Monitoring

Use with GaugeReader 3.0 software

Requires USB/RS485 converter

Real-time data logging capability

7.3 Wireless Operation (Optional)

Pair with WGC150 wireless gateway

Requires external antenna

Same Modbus protocol over RF

8. Physical Dimensions

Weight: 300g (with KF16 flange)

Size: 105H × 50W × 32D mm

Expert FAQs

1. What's the difference between Pirani and other vacuum gauges?

Pirani gauges are ideal for rough to medium vacuum (10⁻¹ to 10⁵ Pa), offering fast response and good durability compared to more fragile high-vacuum gauges.

2. How does gas composition affect measurements?

The gauge is calibrated for air/N₂. For other gases, apply correction factors (e.g., 0.8 for He, 1.7 for Ar). Full gas correction table available in manual.

3. Can I use one gauge to monitor two chambers?

Yes, with optional dual-sensor configuration (WPI200-D model).

4. What's the recommended calibration interval?

Annual calibration is recommended for critical applications. The gauge features built-in calibration routines for atmosphere and zero adjustments.

5. How to integrate with PLC systems?

Choose either:

Analog output (0-10V) for simple systems

RS485 Modbus for networked applications

Relay outputs for alarm/control functions

6. What's the maximum cable length?

100 meters with standard cable (8×0.14mm²). For longer distances, use RS485 with proper termination.

7. Can it withstand vacuum system bake-out?

Sensor withstands up to 150°C, but electronics should remain below 45°C.

8. How to select analog output range?

Use front panel menu to choose between:

+2.286V to +10.0V (wider range)

+2.5V to +8.5V (higher resolution at low pressure)

9. Is the display readable in bright light?

High-intensity 5-digit LED display remains visible in various lighting conditions.

10. What maintenance is required?

Minimal maintenance needed. Periodically check:

O-ring seals

Electrical connections

Sensor cleanliness