Measurement and Control

Active gauges are a complete self-contained head and driver electronics in a compact unit. These gauges typically need 24Vdc and then provide a 0-10V output that relates to the pressure. This output can be S-shaped or Linear depending on the chosen unit. The benefits of active gauges are:

. Units are compact and efficient due to the use of low power surface mount integrated circuit electronics

. Flexible cables can be used as they only contain a drive voltage and high voltage output signals rather than low voltage signals that could be prone to interference

. Non-specific controllers eg TIC and AGD can be used that can control multiple gauges without needing to specify exact gauges to use at time of ordering

Digital gauges are similar to Active in that they are self-contained including driving electronics, however they take this one step further and eliminate the need for a separate controller. The Digital gauges simply need a supply voltage in the range of 15 to 48Vdc and then are serial comms enabled, so can be directly interrogated via a PC or PLC using either RS232 or RS485 communications. The benefits are:

. Elimination of an external controller reduces overall costs, where serial communications can be used 

. Units are compact and efficient due to the use of low power surface mount integrated circuit electronics

. Long standard flexible serial cables can be used (although an external power supply will be required)

Passive gauges completely separate the measuring part from the driver electronics. The head that is attached to the system only contains the items needed for the physical measurement and all other electronics is contained in the controller. As such the controller and cable have to be specific to the desired gauge. The benefits are:

. Gauge head is less prone to interference such as that from ionizing radiation

. Gauges and connectors can be more rugged making them suitable for industrial environments

Portable gauging offers the opportunity to be free of cabling and power and take spot measurement checks. The Edwards P3 handheld all in one measuring system is the essential device for on-site service calls and on the spot flexible checking due to it being mains power independent

• Direct display of measurement values
• Internal storage and display of up to 2000 data points with ability to export to PC
• Optional accessory kit with carry case.