Hydraulic pressure monitoring for critical construction projects

28 March, 2023

“Installing this technology onto any site has its challenges, but this is particularly true for construction”, Price explains. “On-site, you have variable weather conditions and there are often moving vehicles and bulky building materials that could block the transmission of data. In some cases, whole new buildings will be erected, which will make it difficult for signals to penetrate. Therefore, the devices chosen needed to be able to transmit data over a large area, be weather-resistant and durable to withstand vibrations made by heavy machinery.”

Hydrotechnik has been involved in the sale of temperature and pressure flow test kits for some time. So, when customers started looking to do all of this wirelessly, the company sought help from wireless test and measurement equipment specialist, Mantracourt.

Price explained: “Because Mantracourt operates in parallel worlds to us, we did have some reservations going into the partnership. Mantracourt’s industry experience is in strain gauge and weighing, whereas we cover pressures in pipes, linear movement and vibration monitoring.

“However, our reservations were premature, and we quickly discovered the relationship to be of mutual benefit. We worked closely with a team of electronics engineers to marry up what we do well — hydraulic monitoring — with what Mantracourt has been doing well with wireless telemetry electronic devices.”

Exeter-based Mantracourt Electronics designs and manufactures signal conditioning equipment and sensor systems, specialising in wireless telemetry and cloud-based remote monitoring. The instrumentation sold for the Thames project was packaged under Hydrotechnik’s Watchlog Wireless branding.

Tom Lilly, application engineer at Mantracourt, explained that the Watchlog system comprises of ten bridge-based pressure sensors, each bolted to a standard IP67-rated T24 transmitter enclosure: “Signals from these sensors are wirelessly transmitted up to 800 metres to an optional solar powered wireless range extender, which will then send the data to the base station installed in the construction site’s main office. Finally, the Watchlog system uses the T24LOG100 software so users can view live data, set alarms and log data when needed.”

However, it has taken Mantracourt and Hydrotechnik a few years of collaboration to fully optimise the solution. One challenge the team faced in the early days was with the settling times of the sensors slowing the efficient gathering of data.

Lilly explained: “We were bolting conditioned sensors, that give an analogue output of 4-20 mA/0 10 V, to the enclosures of standard T24-ACMi-IA/VA transmitters. However, settling times were interfering with the accuracy of the readings and general productivity of the projects. T24 powers down after every transmission to conserve battery power and often sensors must then spend time warming up before they can take readings. The continuous process of warming up and powering down adversely affected the system’s battery life and affected the noise-free resolution and stability of the data.

“An option was for us to change the gain resistor in the standard T24 SA product. This increased the maximum input capacity from three millivolts per volt (mV/V) to 20 mV/V so it is compatible with Hydrotechnik’s non-conditioned sensors that give a Wheatstone Bridge output. It’s only a small change, but for the Mantracourt and Hydrotechnik teams it’s like a brandnew product that can be used on all non-conditioned sensors.”