9.23 Equivalent electric circuit of pH sensor
9.24 Effects of temperature on asymmetrical potential
9.25 Operating principle of an IsFET sensor
9.26 ORP tracking nitrification and denitrification in SBR
9.27 Comparisons of two ORP electrodes
9.28 A diagram of a streaming current monitor unit
9.29 Double diffuse layer and zeta potential
9.30 Fractions of nitrogen
9.31 Fractions of phosphorus
9.32 Fractions of TOC
9.33 Flow path for typical HTC analyzer
9.34 Flow path of a typical heated persulfate UV analyzer
9.35 Ultraviolet spectra of humic and tannic acids
9.36 Typical fixed-wavelength sensor configuration
9.37 Typical spectra from a scanning-type UV-vis optical sensor
9.38 Example of one type of scanning photometer configuration
9.39 Typical installation for a high-temperature TOC analyzer, including a sample preparation or processor, the analyzer, and gas and water supply
9.40 Biochemical oxygen demand analyzer
9.41 Typical installation of a dichromate, colorimetric analyzer and filter assembly
9.42 Illustration of how backscattered light principle instrument works
9.43 Sludge core sampler
9.44 White light turbidity method
9.45 Near-infrared turbidity method
9.46 Force, couple, dynamic, and overhung rotor unbalances
10.1 Components of a final control element
10.2 A comparison of traditional and digital controls
10.3 Control valve characteristics
10.4 Types of valves
10.5 Solenoid valve
10.6 Types of pumps
10.7 Types of electric motors
10.8 Three-phase starter
11.1 Communications are found throughout automation systems between a wide range of device and system types
11.2 Digital communications technology now allows for direct connection of I/O devices to higher-level systems, in addition to PLCs using Ethernet and other fieldbus technologies, to provide device health and diagnostic information and I/O state data
11.3 The RJ-45 connector
11.4 Typical DB-9 serial male connector
11.5 The three layers that make up many types of communications networks
11.6 Example serial communications network, including RS-232 and RS-422 networks
11.7 Example connection to a proprietary PLC network. Notice the network interface card required in the HMI or SCADA system computer
11.8 Ethernet encapsulation allows serial devices to communicate over Ethernet using cost-effective Ethernet/serial convertors when paired with OPC server software that supports Ethernet encapsulation
11.9 Example of enabling Ethernet encapsulation in an OPC server
11.10 Variable-speed drives and PLCs connected using Ethernet encapsulation
11.11 Example architecture using an Ethernet/proprietary network bridge
11.12 Configuring an OPC server to communicate through a Modbus TCP to Modbus Plus Bridge
11.13 Device protocol diagnostics screen in an OPC server
11.14 PortMon serial port monitoring utility
11.15 Example OPC server application configuration to monitor network switch port bandwidth use
11.16 Network monitoring and troubleshooting application designed for use by control and automation engineers
11.17 Example of an OPC server application that can be configured to read computer system health indicators, notify of problems via e-mail, and deliver the same information to HMI or SCADA screens
11.18 Example of a manufacturer’s embedded Web page
11.19 Example of configuring redundancy for devices and network media in an OPC server
11.20 Device connectivity without OPC requires each application vendor to write his or her own drivers to talk to each device brand
11.21 Using OPC for device communications separates communications details from the application
11.22 Example OPC server software user interface
11.23 Example OPC client software user interface
11.24 Browser-based HMI example