Campbell Scientific SCADA (Supervisory Control and Data Acquisition) systems consist of a supervisory computer running HMI (Human-Machine Interface) software and control units performing data acquisition and control functions. The control units make measurements as well as report back to and execute commands from the supervisory computer. The versatility and reliability of our control units set our systems apart from others. These units provide many benefits that PLCs do not.
SCADA System Benefits
- Control units function as PLCs, RTUs, or DCUs.
- Control units perform advanced measurement and control independent of the central computer.
- PID control continues, even if communications to the main computer are lost.
- Control units have many channel types to measure most available sensors.
- Systems are compatible with our own or other vendors’ HMI software packages.
- Control units have their own UPS (during AC power loss, they continue to measure and store time-stamped data).
- Control units provide on-board statistical and mathematical processing.
- Systems are easily expandable: add new sites or add sensors to existing sites.
- Control units have wide operating temperature ranges and operate in rugged environments.
SCADA Control Units
Our control units, the CR800, CR850, CR1000, CR3000, or CR5000 function as PLCs (Programmable Logic Controllers), RTUs (Remote Terminal Units), or DCUs( Distributed Control Units). These control units can be linked using Ethernet (10 or 100 Mb Tlink) or other communications options. Because they have their own operating systems, control units can be programmed, without ladder logic, to perform advanced measurement and control functions. This eliminates the need for the supervisory computer to do the minute-by-minute control and data acquisition and means that PID control continues, even if communications to the supervisory computer are lost. The control units also provide on-board statistical and mathematical capabilities for data reduction at the remote site and can store up to 2 million time-stamped data points, depending on the model used.
Another major advantage of these systems is that they are easily equipped with an Uninterruptible Power Source (UPS), typically rechargeable batteries and/or solar panels. During power loss, they continue to measure and store time-stamped data, which can be later transmitted to the supervisory computer.
Almost any sensor may be used with the measurement and control system, allowing customization for each operation. Each of these control units features a variety of channel types for flexibility in measuring many different types of sensors. For example, magnetic flow meters can be measured using pulse counting channels instead of being measured as a 4-20 mA signal. Likewise, ultrasonic level transmitters can be measured using SDI-12 protocol on digital ports instead of as a 4-20 mA signal. Our control units also provide extensive signal conditioning and are easily expandable.
The control units support multiple communications options, including: Ethernet, radio, telephone, cellphone, voice synthesized phone, and satellite. They also feature peer-to-peer event and polled communication, and can call out to a computer, telephone numbers and/or pagers. Remote lift stations, reservoirs, and pumping stations transmit data via dial up leased phone lines, cell phone, radio, or wide area network T1 links.