Siemens BPZ:QAC3171 Universal Temperature Sensor

The Siemens BPZ:QAC3171 Universal Temperature Sensor is a robust and precise instrument designed for critical temperature monitoring in HVAC systems and building automation. Its core strength lies in its reliable Pt1000 sensing element, ensuring accurate measurements across a wide temperature range. The sensor's active 4-20 mA output signal provides a standardized, interference-resistant method for data transmission to control systems and Building Management Systems (BMS), making it a versatile component for modern industrial applications.

Product Specifications

| Specification         | Value                                       |

| :-------------------- | :------------------------------------------ |

| Sensing Element       | Pt1000                                      |

| Measuring Range       | -50 to 50 °C (-58 to 122 °F)                |

| Measurement Accuracy  | ±0.9 K at -50 to 50 °C                      |

| Analog Output Signal  | DC 4-20 mA                                  |

| Operating Voltage     | DC 13.5–35 V                                |

| Power Consumption     | ≤ 1 VA                                      |

| Time Constant         | 1200 s (20 min)                             |

| Connection            | Screw terminals                             |

| Degree of Protection  | IP65                                        |

| Housing Material      | Polycarbonate                               |

| Dimensions (W x H x D)| 80 x 88 x 39 mm                             |

| Operating Temperature | -50 to 50 °C                                |

| Mounting              | Outdoor or room installation                |

| Manufacturer          | Siemens Smart Infrastructure                |

| Manufacturer Part No. | QAC3171                                     |

| Alternative Part No.  | BPZ:QAC3171                                 |

Core Features & Market Positioning

The Siemens BPZ:QAC3171 distinguishes itself through its industrial-grade construction and high-accuracy Pt1000 sensor, a standard for reliable temperature measurement. Its IP65 rating signifies excellent protection against dust and water ingress, making it suitable for exposed outdoor installations. The active 4-20 mA current loop output is a significant advantage, offering superior noise immunity over voltage signals, especially over longer cable runs, which is crucial for maintaining data integrity in industrial environments. This sensor is positioned as a high-quality, dependable solution for applications demanding precise and consistent temperature data for control and monitoring purposes.

Key Application Scenarios

The versatility of the Siemens BPZ:QAC3171 makes it indispensable across various HVAC and building automation applications. It excels as an outside air temperature sensor, providing critical data for economizer control, heating/cooling load calculations, and weather-dependent setpoint adjustments. Within buildings, it functions effectively as a room temperature sensor in commercial spaces, contributing to precise climate control and occupant comfort. Furthermore, it serves as a valuable measuring sensor for system optimization, performance monitoring, and integration into sophisticated Building Automation and Control Systems (BACS).

Practical System Integration Guidance

Integrating the Siemens BPZ:QAC3171 into an existing system is straightforward due to its standard 4-20 mA output. Wiring involves connecting the sensor's terminals to the appropriate inputs on a BMS controller or data acquisition unit. Typically, a two-wire connection is used where the power supply and the signal share the same pair of wires. It is essential to use twisted-pair cabling for the signal lines to minimize electromagnetic interference, especially in environments with high electrical noise. When sizing power transformers, consider the sensor's low power consumption of ≤ 1 VA. For optimal performance and to prevent measurement errors, ensure the sensor is mounted away from direct heat sources or drafts that could skew readings. Refer to the product datasheet for specific wiring diagrams and terminal connections.

Operation and Risk Mitigation

Proper operation of the BPZ:QAC3171 relies on correct installation and wiring. The sensor is designed for a temperature range of -50 to 50 °C, and operating outside these parameters could lead to inaccurate readings or damage. The IP65 rating provides robust protection, but care should still be taken to avoid prolonged exposure to extreme environmental conditions beyond its specified limits. Troubleshooting typically involves checking the power supply voltage (13.5-35 VDC) and verifying the integrity of the 4-20 mA signal loop. An open or shorted loop can indicate a wiring issue or a faulty sensor. Confirming the correct loop resistance and ensuring that the receiving device is configured to interpret a 4-20 mA signal are also critical steps.

Scalability & Long-Term Value

The Siemens BPZ:QAC3171 offers excellent long-term value due to its compatibility with a wide range of Siemens and third-party building automation systems. Its standard 4-20 mA output ensures it can be integrated into new or existing infrastructure without the need for specialized gateways or complex protocol conversions, provided the control system supports analog current inputs. While the sensor itself is not upgradeable, its robust design and reliable performance contribute to the longevity of the HVAC systems it serves. Its integration into BACS facilitates sophisticated control strategies, energy efficiency improvements, and predictive maintenance, enhancing the overall scalability and value of the facility's operational technology.

Frequently Asked Questions

What is the primary function of the Siemens BPZ:QAC3171?

The Siemens BPZ:QAC3171 is primarily an active temperature sensor. It accurately measures ambient temperatures for HVAC control.

It transmits this data via a standard 4-20 mA analog output signal. This signal is ideal for building automation systems.

Its robust design makes it suitable for both outdoor and indoor room monitoring applications.

What is the measuring range of the Siemens BPZ:QAC3171?

This sensor measures temperatures from -50 to 50 degrees Celsius. This range covers most typical HVAC requirements.

It can also be expressed as -58 to 122 degrees Fahrenheit. This ensures compatibility with different regional standards.

The sensor maintains accuracy within this specified operational range.

What type of sensing element does the BPZ:QAC3171 use?

The BPZ:QAC3171 utilizes a Pt1000 sensing element. This is a type of resistance temperature detector (RTD).

Pt1000 sensors offer excellent accuracy and stability over time. They are a preferred choice for precise temperature measurements.

This sensing element allows the QAC3171 to provide reliable data for critical control loops.

How is the Siemens BPZ:QAC3171 powered?

The BPZ:QAC3171 operates on a DC voltage supply. The required voltage is between 13.5 and 35 VDC.

This operating voltage is supplied via the same two wires used for the output signal. This is a common 4-20 mA two-wire configuration.

Ensure the power supply meets these specifications for proper sensor operation.

What is the output signal of the Siemens BPZ:QAC3171?

This sensor provides an active analog output signal. It is a 4-20 mA current loop output.

This current loop signal is robust against electrical noise over long distances. It is a standard in industrial and building automation.

The output signal directly correlates to the measured temperature according to its specifications.

What is the accuracy of the Siemens BPZ:QAC3171?

The QAC3171 offers a measurement accuracy of ±0.9 K. This accuracy is maintained across its specified range.

This level of accuracy is suitable for most HVAC control and monitoring applications. It ensures precise temperature data for system operation.

For critical applications, always verify the sensor's performance against system requirements.

What is the degree of protection for the Siemens BPZ:QAC3171?

The BPZ:QAC3171 features an IP65 degree of protection. This rating signifies full protection against dust ingress.

It also means the sensor is protected against low-pressure water jets from any direction. This makes it suitable for outdoor installations.

This robust protection ensures reliable operation in challenging environmental conditions.

Can the BPZ:QAC3171 be used as a room sensor?

Yes, the QAC3171 can function as a high-quality room temperature sensor. It is designed for this dual application.

Its accuracy and output signal are well-suited for maintaining comfortable indoor environments. It integrates seamlessly into BMS for room climate control.

This versatility makes it a cost-effective solution for multiple sensing needs within a building.

What is the time constant of the BPZ:QAC3171?

The time constant for the BPZ:QAC3171 is 1200 seconds, or 20 minutes. This indicates how quickly the sensor responds to temperature changes.

A longer time constant means the sensor takes more time to reflect a sudden temperature shift. This is typical for sensors designed for stability and averaging.

This characteristic is important for applications where rapid fluctuations are undesirable.

What are the dimensions of the Siemens BPZ:QAC3171?

The physical dimensions of the BPZ:QAC3171 are 80 mm wide, 88 mm high, and 39 mm deep. These compact dimensions facilitate installation.

The housing is constructed from durable polycarbonate, offering protection and longevity. It is designed for straightforward mounting in various locations.

These dimensions ensure it can be discreetly installed in many different environmental settings.