Until now, transmitters with integrated displays and control panels have generally been used to connect sensors for liquid analysis. They process the sensors’ measured values and transmit them to the control system via standardised 4…20 mA Hart signals. Some interconnected applications do not require the values to be visualised on-site or provide only narrow installation spaces that argue against installing additional external devices. Sensors with integrated transmitter units have been available for a few years now for this type of application. However, the components in these systems are permanently connected to each other and every time a sensor is replaced, the transmitter unit – and the measuring loop settings stored in it – must also be disposed of. Configuring the new unit means added maintenance and operating costs. Since Memotrans from Knick has a direct sensor connection, there are no extra costs involved: the compact transmitter and the sensor are separate units.
Simple connection
The electronics in the sensor heads of Memosens sensors digitise the measured values, thus eliminating interference caused by long analogue signal lines. Moisture and deposits on the connector system do not adversely affect signal transmission because the data are transmitted inductively, i. e. without contact, via Memosens couplings. The miniaturised transmitter technology is integrated into the slim housing, which means Memotrans can be directly connected to the loop-powered two-wire system without an additional adapter.
Unlike conventional two-wire transmitters, Memotrans is not limited to one parameter. It is a true all-rounder. Since all Memosens sensors can be used to measure pH/ORP, oxygen (amperometric) or conductivity, Memotrans is ideal for meeting the most diverse requirements. The digital Memosens sensors identify themselves uniquely by means of their sensor ID. After being connected, a red/green LED on the housing indicates whether or not the sensor is connected to Memotrans. To enable technicians to access measuring loops flexibly and conveniently on-site, the device has an integrated Bluetooth interface. Thanks to the Memotrans app for iOS and Android, all current sensor, configuration and diagnostics data can be displayed directly on a smartphone and of course on Hart handhelds.
Communication in the control system
Configuration, the retrieval of diagnostics data, the display of sensor data and calibration can all be carried out via Hart directly in the control room using a corresponding device description (DD). Knick also offers Memosuite, a software tool for easy and reliable calibration and adjustment of Memosens sensors (pH, ORP, oxygen, conductivity and temperature) in the laboratory under defined conditions. This enables quick sensor replacement – with no need for process engineering experts to calibrate on-site under difficult ambient conditions. For calibration with Memosuite, the sensors are connected to USB computer ports via a Memolink interface converter. With Memosuite Advanced, the expanded software version, up to ten sensors can be calibrated at once. All calibration and adjustment data or sensor loads are seamlessly recorded for data management purposes, facilitating complete documentation in accordance with specifications such as FDA 21 CFR Part 11.
With its compact transmitters for Memosens, Knick is paving the way for superior sensor technology in areas where process quality assurance requires a total-coverage measurement loop setup, even in the tightest of spaces. The manufacturer has long provided a four-wire DIN rail compact transmitter for Memosens sensors and now also offers a miniaturised transmitter for two-wire connections.
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Author: Ketty Casonato
Product Manager Process Analytics,
Knick
