Signal port

Fig. 10. Use of solenoid valve for shutdown. Upon signal to shutdown, the solenoid closes a controller air signal port and opens a vent port.

Fig. 1.2 Signal connecting two signal ports in a graph fragment...

Block diagram nodes All nodes that only have signal ports and represent mathematical relations between these signals. These nodes are equal to any type of block diagram definition that exists based on (elementary) mathematical... 

The amount of MW power reaching the sample in the resonator is controlled by a variable attenuator. Like the isolator, the circulator is a non-reciprocal device that serves to direct the MW power to the resonator (port 1 port 2) and simultaneously allows the signal reflected at resonance to go from the resonator directly to the receiver (port 2 port 3). 

Sample times for the microprocessor-based SLCs vaiy from O.I to 0.4 seconds. Low-pass analog electronic filters are installed on the process inputs to stop abasing errors caused by fast changes in the process signal. Input filter time constants are typically in the range From O.I to I s. Microprocessor-based SLCs may be made part of a DCS by using the communication port (RS-488 is common) on the controller or may be operated in a standalone mode independent of the DCS. 

At the compressor exit, predominate frequencies of 48A existed up to speeds of 6800 rpm. At 8400 rpm, the 48A and 86A frequencies were of about equal magnitudes—the only signal where the 48A and 86A frequencies were the same. The pressure was measured from a static port in the... 

When a minimum of signal processing is required, analog data can be input through an A/D unit which plugs in directly to the cartridge port of the ST computer (4.) or into a slot of an IBM. 

The most versatile data acquisition option is a stand alone data collection unit. At Glidden we use an Elexor Data Logger (S) for this purpose. It has its own microprocessor and BASIC Interpreter and communicates with the computer via the serial port. The unit can be configured with a wide variety of signal processing options. 

The actual mode of connection between instrument and computer varies depending on the type of signal generated and the design of the instrument. The connection can be made via a serial port, a parallel port, or a USB port. The electronic circuitry required is built into the instrument s internal readout electronics or into an external box used for conditioning the instrument s output signal. In some cases, the instrument will not operate without the computer connection and is switched on and off as the computer is switched on and off. In other cases, the entire computer is built into the instrument. 

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