Glossary Cateogry: S

The switching voltage indicates the maximum voltage (including residual ripple) to be switched by the relay output.

The switching power indicates the maximum power that can be placed on the output relays.

This relates to capacitive sensors. The operating distances are given for an ambient temperature of 23C. In the permissible temperature range the switching point varies by less than 15 % from the value at 23C. The temperature of the measured object has no influence on the switch point.

This depends on the type of sensor being deployed. For example, capacitive level sensors react to conductive materials and non-conductive materials with a dielectrically constant Epsilon >1. The switching point depends on the material. When the sensor-tip is immersed in a fluid, a switching command inside the device is triggered. This trigger is set between contact with the liquid and some mm more into the liquid. This distance between the tip of the sensor and the trigger is the nominal switching point. The immersion-distance has a negative sign, e. g. -8 mm. The water content of an object or a liquid has a decisive influence on the switching point. A high humidity content increases the switching point considerably. If the sensor is moistened with conductive materials, its function can be impaired when a conductive film builds up, that electrically connects the sensor electrode with a metallic conducting side. For an ultrasonic sensor the switching point is the distance from the sensor face at which the output is switched on or off.

The maximum switching frequency of an inductive proximity switch is determined at half rated operating distance sn with standard measurement plates to EN 60947-5-2

Inuctive Proximity Sensors

This relates to capacitive sensors. The maximum switching frequency of the sensor is determined at nominal switching point Sp when immersing in the water.

The switching current indicates the maximum continuous current for the switching output of the device. For PNP outputs this value applies to an ambient temperature of 25 C. At higher temperatures the maximum switching current is reduced.

The operating distances are given for an ambient temperature of 23°C. In the permissible temperature range the operating distance varies by less than 15 % from the value at 23°C. The temperature of the measured object has no influence on the switch point.

Inuctive Proximity Sensors

The supply voltage is the voltage range within which sensors function safely. For direct current supplies it must be ensured that the limits are maintained even including residual ripple.

The start-up time is the period of time required by the flow detector to reach a stable state after the operating voltage has been switched on. Prerequisite is that the medium flows at the rated velocity and that the sensor has adapted to the temperature of the medium before switching the supply voltage on. The start-up time is prolonged in a static medium and reduced if the medium flows faster than the rated value.

The short circuit protection ensures the sensor against destruction through a short circuit on the output. After removal of the fault, the output is reactivated. Where a maximum overload current is listed, this should not be exceeded.

Devices used to detect and measure products and variables, such as temperature, and to convert such signals into a useable format, such as 4-20mA.

Sensor Solutions
Sensor Applications
Flow Sensors
Level Sensors
Ultrasonic Sensors
Optical Sensors
Colour Sensors

SCADA stands for Supervisory Control And Data Acquisition. So what does this mean? Essentially SCADA is a software package designed to display information, log data and show alarms. This can be graphical and tabular formats, words or pictures. SCADA is used in many industrial processes such as manufacturing, power generation, water and chemical. The size of a SCADA system can vary greatly. SCADA can be used to monitor and control plant or equipment. The control may be automatic, or initiated by operator commands. The data acquisition is accomplished firstly by the RTU’s (Remote Terminal Units, in our case the Metron). The central host will scan the RTU’s or the RTU’s will report in Data can be of three main types. Analogue data (ie real numbers) will be trended (ie placed in graphs). Digital data (on/off) may have alarms attached to one state or the other. Pulse data (eg counting revolutions of a meter) is normally accumulated or counted.