Automatic Test System (ATS) Of Vertical Metal Detectors

Monday, October 8th, 2018

The Automatic Test System (ATS) can decrease the time it takes to complete metal detector performance monitoring tests by up to 90 percent, compared to manual testing processes. By Mettler Toledo.

ATS ensures tests are completed consistently every time for multiple metal types to improve process quality. Routine performance testing is particularly challenging for operators of high speed, vertical or gravity-fed metal detection systems. Introducing metal test samples into free-falling powders, snack food, or confectionery applications and documenting the results takes considerable time and resources. In many cases, the process requires operators to work at height and to reach across equipment, which creates potential risks. ATS addresses each of these challenges.

ATS is a system that can be used to reduce the cost and improve the repeatability of the metal detector’s routine performance monitoring tests. It is designed for use with metal detectors inspecting free-falling products in vertical packing or gravity-fed applications. Once activated, the system automatically tests the metal detector to ensure it continues to operate to the customer’s required quality standard. It does not, however, verify the effectiveness of the reject control system in place.

How ATS Works

Test samples, to a known certified standard, are assembled in discrete acrylic tubes that run up the inside face of the metal detector aperture. The automated pneumatic control transports each test sample in turn, to a defined position above the principle sensing coils within the metal detector. The test sample is then released, simulating the presence of a contaminant in free-fall under gravity.

The ATS test is performed and monitored on the return of the test samples to their original position. The whole process takes less than 30 seconds to complete for a three-metal test, or less than 45 seconds for a four-metal test. The significant reduction in the time required to perform the tests increases productivity. Operator efficiency is improved compared with manual testing.

Only one operator is required to conduct routine performance monitoring tests, and the time taken to conduct the process is reduced considerably. Operator safety is improved when using ATS because it virtually eliminates the need for an operator to work at height or reach across other production line equipment to conduct routine metal detector performance tests.


ATS can be configured to test three or four metal types. The complete system consists of four distributed assemblies: a Pneumatic Control Module, a Tube Assembly, a Control Unit and a metal detector. ATS is not intended for use in hazardous areas.

Pneumatic Control Module

The Pneumatic Control Module houses the Programmable Logic Controller (PLC) and pneumatics. It connects to the Tube Assembly, Control Unit and metal detector. The maximum allowable distance between the Pneumatic Control Module and the Tube Assembly is 2 m.

Tube Assembly

The Tube Assembly is available as a three metal test (as pictured below) or a four metal test option. Ferrous, Non-Ferrous (brass) and Stainless Steel 316 test samples are standard in both. The four-metal option also includes aluminum.

The Tube Assembly is connected to the Pneumatic Control Module via flexible pneumatic pipes and is located onto the external flange of the metal detector. Two thumb screws hold it in place.

Control Unit

The Control Unit enables an operator to start a production test and reset the system should the need arise. The Control Unit can be mounted up to 30 m from the Pneumatic Control Module in a position that is convenient for regular operator use, making it ideal for applications where the metal detector is installed in a location that is not easily accessible. The ATS operating and test status is clearly visible via the metal test indicators.

Benefits Of ATS

Having ATS present in the line can improve productivity by reducing the time taken to conduct routine performance tests by up to 90 percent, Moreover, it also enhances operator safety by reducing or virtually eliminating the need to work at height or reach across equipment to conduct tests as well as improve process quality by enhancing repeatability of test processes.


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