Application and maintenance of Atlas Copco SRTT-B torque sensor

4.1 Mechanical fixation requirements

The sensor base is equipped with mounting holes (4 Ø 6.5 through holes for small range, 4 Ø 8.5 for medium range, and 6 Ø 8.5 for large range), which must be firmly fixed to a structure that can withstand reaction torque through bolts. The parallel planes on both sides of the base can also be used for clamping. Loose fixation can lead to measurement drift and even damage to the sensor. The specific external dimensions (A, B, C, etc.) can be found in the mechanical drawings in the document. The weight range is from 1.4 kg (small range) to 10.7 kg (2000 N · m model).

4.2 Tool Connection Method

Square drive model (≤ 10 N · m): Insert the square tenon of the tool directly into the square hole in the center of the sensor, and lock the side lever to fix it.

Hexagonal model (≥ 25 N · m): The top of the sensor has a hexagonal groove, and the corresponding coupling simulator (TJ series) or dedicated adapter needs to be installed before connecting the tool. At this time, the locking lever is located on the side of the sensor body (the document illustration indicates that the lever only exists in hexagonal drive models).

Operation key: Avoid generating lateral force (radial force). When applying torque, the tool axis should strictly coincide with the sensor axis. Tilting or eccentric loading can introduce bending components, seriously contaminating the measurement results.

4.3 Electrical Connection and Data Reading

Connect the sensor and measuring instrument using the standard 19 pin cable:

If using ACTA series instruments, the EEPROM automatically transfers all calibration parameters without the need for manual input.

If a third-party instrument is used, it is necessary to manually input the shunt calibration value (marked on the sensor label) and the number of angle pulses (if angle measurement is required). Attention: The sensor bridge circuit is 350 Ω, and the parallel calibration resistance value is 43.575 k Ω (this is the recommended standard value).

Attachment System and Extended Applications

SRTT-B can be adapted to various mechanical coupling simulators (TJ series) for simulating joints of different hardness to test the automatic shutdown performance of shut off tools. Simulators are divided into two types: "S" (rigid) and "H" (high rigid), corresponding to different tool interfaces:

Simulator model, sensor range, tool interface, rated torque (N · m), order number

TJ SRTT-B S – 0.5 / H – 0.5 0.5 HEX ¼" 0.5 8059 0940 01 / 02

TJ SRTT-B S – 2 / H – 2 2 HEX ¼" 2 8059 0940 03 / 04

TJ SRTT-B S – 10 / H – 10 10 HEX ¼" 10 8059 0940 20 / 21

TJ SRTT-B S-25/H-25 25 25~250 half "square drive 25 8059 0940 07/08

TJ SRTT-B S-500/H-500 500 500~2000 three-quarters "square drive 500 8059 0940 15/16

TJ SRTT-B S-1000/H-1000 1000 1000~2000 1 "square drive 1000/2000 8059 0940 17/18

Attention: The rated torque of the simulator must be equal to or greater than the range of the sensor itself (e.g. SRTT-B 250 cannot be equipped with TJ-25, should be equipped with TJ-250). In addition, there is also the "QAT Accessory adapter" series square drive conversion head, which can convert hexagonal drive sensors into half ", ¼" or 1 "square drives, making it convenient to use wrenches with different interfaces.

Key points of calibration management and maintenance

6.1 Mandatory Requirements for Annual Calibration

The document clearly states that "to maintain accuracy, sensors must be calibrated regularly" and recommends once a year. The sensor label will indicate the latest calibration date and the next calibration date, as well as the calibration source (such as a factory or certified laboratory). The sensitivity, linearity, and other data stored in the internal EEPROM are updated during each calibration. Users should input the actual value on the calibration certificate provided by the original factory (rather than the nominal value on the nameplate) into the third-party instrument.

6.2 Daily Inspection and Fault Avoidance

Overloading is strictly prohibited: Overloading beyond 25% of the rated value will cause strain gauges to yield and sensors to permanently fail. If there is an unexpected overload during testing, it should be sent for inspection immediately.

Environmental protection: Avoid splashing water, high humidity (>75% non condensing), and drastic temperature changes. For every 10 ℃ temperature change, the zero drift can reach 0.1% of the full range.

Electrical interference: Keep away from strong electromagnetic interference sources such as arc welding equipment, otherwise signal noise will mask the true readings.

No user repairable parts inside: any disassembly will automatically invalidate the warranty, and all maintenance must contact Atlas Copco authorized service point.

6.3 Scrapping and Environmental Disposal

The sensor complies with the EU WEEE Directive (2002/96/EC), and its product body and components (including batteries) are marked with a forked trash can symbol. Within the European Union, scrapped equipment must not be mixed with unclassified municipal waste and must be collected and recycled separately in accordance with local regulations to facilitate material reuse and reduce environmental burden.