Application and maintenance of Atlas Copco SRTT-B torque sensor

Atlas Copco SRTT-B Static Torque Sensor: Professional Guide to Selection, Operation, and Full Cycle Maintenance

In the field of bolt tightening quality control, the accuracy of torque measurement is directly related to product safety and reliability. The SRTT-B series static reaction force torque sensor launched by Atlas Copco, as an upgrade model of the previous generation of products, provides a more stable and intelligent solution for torque testing with a new mechanical design and built-in storage technology. This article combines official technical documents to systematically review the core features, selection points, installation and operation specifications, accessory configuration, and daily maintenance strategies of SRTT-B from an engineering application perspective, aiming to provide on-site engineers with a practical manual that can be accessed at any time.

Product positioning and core design innovation

SRTT-B belongs to the static reaction force torque sensor, designed specifically for testing torque wrenches (including click wrenches), tightening tools, and measurement scenarios that require avoiding rotational movements. Its typical applications include:

Perform torque verification on pneumatic or electric shut off tools (in conjunction with a mechanical coupling simulator);

Regularly inspect the output accuracy of the tightening gun on the production line;

Standard transmission and calibration comparison in metrology laboratories.

Compared to earlier models, the most significant improvement of SRTT-B lies in the patented new system of the top fixed coupling simulator. The clearance between the sensor and simulator in the old product may introduce measurement errors, but the new design eliminates this clearance through a rigid locking structure, ensuring that there is no gap in the torque transmission path and thus improving repeatability. In addition, the EEPROM chip built into the sensor base can store the identification code, calibration value, sensitivity (2mV/V), pulse number, serial number and the latest calibration date. When connected to Atlas Copco's ACTA series measuring instruments, all parameters will be automatically loaded, completely eliminating the risk of manual input errors.

In depth interpretation of technical specifications

Understanding key technical parameters is a prerequisite for correct selection. SRTT-B covers 11 range models from 0.5 N · m to 2000 N · m, with the following core specifications:

Parameter item specification value

Measurement range: 20% to 100% of rated capacity (ensuring accuracy within this range)

Static accuracy ± 0.5% (percentage of indication, non full scale)

Overload capacity: 125% of rated capacity (overloading is strictly prohibited, otherwise the strain gauge will permanently yield)

Temperature stability 0.1% capacity/10 ℃ (to be used in a constant temperature environment)

Bridge resistance 350 Ω

Working temperature and humidity: 5~40 ℃, 10%~75% RH (no condensation)

Excitation voltage ± 5 VDC (provided by measuring instrument)

It should be noted that 'static accuracy' is only applicable to smooth and impact free loading processes. The document clearly warns that SRTT-B is not suitable for impact tools (such as impact wrenches), as transient pulses can damage internal strain elements. In addition, the principle of "adapter torque superposition" must be followed in practical use - when multiple conversion joints are connected in series, the maximum allowable torque of the entire chain depends on the joint with the smallest rated value and cannot be exceeded.

Model system and selection matching strategy

The naming convention of SRTT-B intuitively reflects the range and drive interface:

Model Capacity (N · m) Drive Method Order Number

SRTT-B 0.5-13 0.5 half "square drive 8059 094 03

SRTT-B 2-13 2 half "square drive 8059 094 09

SRTT-B 5-13 5/2 "square drive 8059 094 15

SRTT-B 10-13 10/2 "square drive 8059 094 21

SRTT-B 25-36 25 36 mm hex 8059 094 28

SRTT-B 50-36 50 36 mm hex 8059 094 36

SRTT-B 100-36 100 36 mm hex 8059 094 45

SRTT-B 250-36 250 36 mm hex 8059 094 64

SRTT-B 500-50 500 50 mm hex 8059 094 63

SRTT-B 1000-50 1000 50 mm hex 8059 094 75

SRTT-B 2000-50 2000 50 mm hex 8059 094 84

The golden rule for selection: The rated capacity of the sensor should be greater than or equal to the maximum output torque of the tested tool, and it is recommended to reserve more than 20% of the margin (because the accuracy guarantee starts from 20% capacity, and if the tool torque is lower than 20% of the sensor range, the accuracy will decrease). For example, when testing a tightening gun with a maximum torque of 800 N · m, the SRTT-B 1000-50 model should be selected instead of the 500 model. At the same time, pay attention to the matching of the drive interface - the small range (≤ 10 N · m) is a half inch square drive, the medium range (25-250) is a 36mm hexagonal drive, and the large range (500~2000) is a 50mm hexagonal drive. If conversion is required, a dedicated adapter (see below) should be used.

Detailed explanation of the entire installation and operation process