Tietjen & JUMO: Modern remote maintenance concept

"Industry 4.0" worldwide – Automated speed control for hammer mills with remote maintenance

Tietjen Verfahrenstechnik GmbH has been building hammer mills for a wide range of applications since 1959. The company has recently been using JUMO control technology to control the dosing systems. Together with JUMO Engineering, the company has also developed a modern web application to promote the innovative Tietjen remote maintenance concept for hammer mills. The result of the fruitful cooperation is a JUMO controller in Tietjen design that is optimally tailored to the application with customer-specific software. The milling systems of the company are mainly used in the field of feed and food production, but also for the crushing of wood and fibres as well as biowaste/biomass. The systems are designed to be customer-specific, to implement a high standard in the control system. An important component for the efficiency of each mill is the upstream dosing device. In particular, plants for biomass digestion usually require a dosage of the substance input. For dry material, many systems require aspiration, i.e. an air flow that supplies resulting dusts for separation. In addition, no contaminants such as metals, stones or plastics should enter the process.

High-precision control required
Depending on the application, screw, vibration, or drum dispensers used, the speed must be closely monitored so that the defined amount of grinding material is always supplied. The aim is to operate the drive motor of the grinding unit as far as possible in the optimum operating range. There are also a number of other challenges to be addressed, which determine the requirements of the system. Depending on the grinding material, the system reacts differently, and the controller parameters must be precisely adjusted. In addition, the start of such a plant is difficult, because depending on the type and structure of the supply, it can take a while for the grinding material to be continuously dosed. During this time, the controller must not become unstable, as an overdose leads to a standstill of the plant and requires manual intervention up to emptying the entire system.

Last year, Tietjen Verfahrenstechnik GmbH was looking for a new and more modern controller component for this task, which in particular offered functions under the general term of "Industry 4.0", such as a remote maintenance option. The main task is to control the speed of the electric drive of the dosing depending on the load on the grinding unit. A continuous PD controller with conventional analogue input and output as well as a power supply of 24 V was required. The controller must have UL approval for export and is installed in a control cabinet. An external controller release and the setting of an external setpoint should still be able to be realized by means of a higher-level controller. Switching on additional temperatures for system monitoring is optionally provided. The JUMO DICON touch is a multi-channel process and program controller with a modular hardware concept that enables use in a wide range of applications.

In addition, the JUMO DICON touch also offers useful functions for this application, such as time-dependent parameter set switchover or, alternatively, start up ramp. Furthermore, limit values can be defined, which cause the switching off of the controller and thus the standstill of the dosage in case of grinding mill overload. 

Modern remote maintenance concept
In order to make the hammer mills suitable for remote maintenance, as well as to enable the simplest possible operation and commissioning by service personnel on site, or from the service department of Tietjen Verfahrenstechnik GmbH, all JUMO DICON Touch or TCU 96 (customer designation of the OEM device) are delivered with a specially developed, customer-specific web application.

Together with Tietjen Verfahrenstechnik GmbH and JUMO Engineering, the extensive requirements for an "Industry 4.0"-capable system were implemented. The result was implemented as a standard on the device-side web server. The web server can be reached in various ways. E.g. via a local WiFi with a laptop, tablet or smartphone, as well as via a VPN gateway, or a customer-side network structure at the end customer via DSL. The application is designed only for the operation of the system, as well as for its remote commissioning or optimization. Corresponding configuration parameters can therefore only be accessed with password protection and in a separate configuration environment. The controller is operated during operation without password protection. With this web application, Tietjen Verfahrenstechnik GmbH is able to seamlessly map its sophisticated remote maintenance concept.

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