Online condition monitoring with fieldbus interface
22 November 2018 | Web Article Number:
VSE150 is a six-channel diagnostic system designed to evaluate four dynamic signals (e.g. rotational acceleration) and two analogue inputs.
According to local distributors IFM Electronics, the new VSE15x family provides different fieldbus interfaces to exchange data with a PLC. This makes it possible to display the measuring values directly on the control system and optimally adapt the monitoring functions to the operating states and processes of the machine.
In addition to the fieldbus, two fast digital switching outputs (response time ≤1 ms) are provided for time-critical alarms.
The direct PLC connection via fieldbus allows auxiliary parameters (e.g. rotational speed and triggers for operating states) as well as non-time-critical alarms from condition monitoring to be exchanged over the bus. This not only reduces wiring complexity but also saves the cost of providing the corresponding inputs/outputs on the PLC.
Machines with varying processes such as machine tools have high demands on condition monitoring systems. “To recognise deterioration in quality at an early stage and avoid scrap or even damage, a process-dependent detection of even the smallest change is necessary,” the company said in a statement.
It added that this can only be achieved by interlinking the operating parameters (e.g. rotational speed, power consumption, feed rate, tool) and the vibration data – ideally in the PLC. “This combination of control and condition monitoring data enables process-dependent monitoring, leading to a considerable increase in quality and process reliability. The same applies to diagnosis (rolling-element bearing condition, ball screw, unbalance), where, in many cases, a high degree of diagnostic validity can only be achieved by combining the vibration monitoring data with the machine/process parameters of the PLC.”
Influencing process factors must be minimised and the measured data evaluated systematically. “Here, too, integrating condition monitoring with the PLC is an enormous advantage and a direct fieldbus connection provides the optimal solution,” the company said.
“If machine protection (e.g. crash monitoring) is part of the monitoring concept of a machine, a fast response is critical to minimise potential damage. Here, reaction speed is everything. For time-critical alarms, the diagnostic electronics provides two additional digital outputs.
“The response time of the diagnostic electronics from the time the event occurs until the switching output reacts is 1 ms. This signal can be used to initiate an immediate machine stop to protect man and machine and minimise or even completely avoid consequential damage.”