APMT high-precision humidity transmitter
The Angst+Pfister Sensors and Power (APSP) newly developed APMT humidity/dew-point transmitter is targeting many various applications in the electronics, chemical, medical, pharmaceutical and materials processing industries, in which humidity monitoring and control is crucial for the quality or goodness of the product to be produced or processed. Such diverse applications as additive manufacturing (AM) over medical air to food preservation drying can benefit from the new APMT dew-point transmitter, because the transmitter is highly reliable, very accurate and the cost-of-ownership are particularly low in comparison with other trace humidity transmitters.
The APMT transmitter has a very long operational lifetime with no drift issues and an easy and low-cost service concept.
Simple to install and maintain, the APMT transmitter series measures humidity content and dew point in a gas sample and the transmitter is available with a broad range of industry standard process connections. The APMT features analog or digital outputs for a broad compatibility with any electronic controller, and it comes with an easy-to-use self-service concept with a very short downtime needed when servicing the transmitter. The ceramic sensor body with screen-printed platinum interdigitated electrodes is covered with a humidity sensitive phosphor pentoxide (P2O5) layer, which can easily be reapplied in regular service intervals (6 months is recommended by intensive use of the transmitter) and in combination with other routine maintenance procedures.
The APMT dew-point transmitter has a humidity measurement range from 0 to 500 ppmv (-100°C to 20°C dew point range). In the standard version, the sensor head is applied to the application using the G1/2” BSP process connection and the sensor head and the transmitter unit is connected to each other using standard cables with M12 connectors. The standard output signal from the transmitter is 4-20 mA, but serial, digital output interfaces are also available. The analogue output is scalable within the measurement range via a RS232 interface. A special version of the APMT dew-point transmitter measures humidity in the range from 1 to 20.000 ppb.
The sensor front-end reacts within 5 seconds (T90) when the atmosphere is changing from a dry state to a wet state. This is very important for processes, where a dry state is being monitored and where humidity in the process must be avoided. Because of the robust ceramic sensor body and the use of platinum interdigitated electrodes, the sensor head is robust against corrosive components in the gas.
In many critical GxP applications, like semiconductor, medicine or pharmaceutical product manufacturing, a high accuracy and equally important a very good signal repeatability is important for the process control plan. The APMT 0-500 ppmv transmitter has an impressive accuracy of +/-0.08 ppmv for low concentration humidity measurements and the signal repeatability is better than +/-0.04 ppmv. The high accuracy, in combination with the highly stable signal output and fast response to humidity concentration changes, means that humidity levels < 1 ppmv can easily be measured and level changes ~ 0.1 ppmv tracked.