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WIKA was the first company to produce a true OEM pressure transmitter with self-diagnostics, designed specifically to meet the challenges of pressure measurement in mobile working machines. The MH-3 has been successfully tried in the field and is a proven solution that’s used by major manufacturers of tractors, harvesters, and sprayers in the U.S.

In 2015, WIKA introduced the MH-3, an OEM pressure sensor with self-diagnostic features to meet the needs of the mobile working machine market. Before the debut of this innovative pressure transmitter, manufacturers were frustrated by unnecessary sensor replacements and the warranty costs associated with sensor failures. What they needed was a pressure measurement instrument that could diagnose whether a failure was due to the sensor itself or some other part of the system. 

An Innovative Pressure Measurement Solution

When a mobile working machine breaks down, the sensor is often not the culprit. But since it’s hard to know the exact reason for a malfunction, many technicians in a rush to get the machine back into service simply replace the sensor and send the old one – whether or not it is actually faulty – back to the factory for a warranty claim. What the MH-4 pressure sensor does is to take the guesswork out of the equation. Its built-in diagnostic function allows troubleshooting directly in the field, keeping replacement of components and downtimes to a minimum.

The MH-3 runs power-up and run-time routines that check, in both the pressure sensor circuit and the temperature compensation circuit, for:

  • Open circuits
  • Shorts to ground
  • Shorts to sensor supply

The routines also check power supply, memory, internal clock, overpressures, and underpressures. Errors are displayed via a defined signal level (error condition indicator) and stored in the pressure transmitter. In the case of a temporary failure, the sensor continues to operate normally but sends a predefined signal to the machine’s onboard software.

In addition, the MH-3 offers signal clamping. Limiting signals to defined levels helps to avoid erratic behavior, premature component failure, and unnecessary shutdowns due to undefined or out-of-range signals. Temporary failure signals, permanent failure signals, and clamping signals are all highly customizable and give field technicians the information they need to quickly identify problems and get machines back into service with minimum downtime.

The MH-3 was designed for load monitoring, load moment indication, hydraulic drive control, and other mobile machine applications. It is encased in reinforced fiberglass thermoplastic and has a hermetically welded thin-film measuring cell, a metallic shield for EMC resistance, and IP69 ingress protection. This compact device is extremely resistant to temperature, shock, vibration, and pressure spikes. Due to its innovative features, major manufacturers of tractors, harvesters, and sprayers in the U.S. have already adopted the MH-3 as their pressure transmitter of choice.

WIKA’s pressure measurement experts are in constant contact with customers to meet the evolving needs of the mobile working machines market. Watch this video and speak with our product specialists to find out more about the MH-3 pressure sensor and other innovations.

Click here to learn more about WIKA product applications in mobile working machines. 

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