Videographic recorders can be used as an alternative to circular chart recorders to keep records while cutting down on the need for paper files.
Once such recorder is used to record pressure and flow in a monitoring well operated by a wastewater plant in Florida. Data recorded by the system is used to satisfy Florida Department of Environmental Protection reporting requirements.
The data is monitored on a Memo-Graph Visual Data Manager (VDM), a videographic recorder from Endress+ Hauser. The system is both a videographic recorder using new technology and a compact measured-values acquisition system with a high-resolution color display.
The system plots signals, monitors setpoints, analyzes measurement points, stores the data internally and archives the information on diskettes. The unit is multi-channel ? it can analyze up to seven digital inputs once per minute, 8 to 16 analog inputs, and four mathematics channels.
Since it does not record data mechanically, it can operate without wear and tear.
The videographic recorder uses E+H ReadWin software for personal computers. The software allows users to set up the recorder, then read out or transfer stored data to a PC. Data can then be displayed in a graphic or tabular format. The software is made up of several components, including a Microsoft Excel Spreadsheet for calculation of internal and diskette memory for Memo-Graph. The application allows users to store unit settings in a database with up to 1000 units. Users can tap into distant units using a modem connection.
It has interfaces for setting up and data transmission. The software also comes with tamper-proof features and can allow more than one user to access the measured value data bank contained on a network.
Memo-Graph units also can be fitted with customized application software, or the company can develop customer-specific software for special applications.
The system is programmed for limit and self-monitoring functions and has an understandable grouping of channels.
The system includes a complete search function to find specific information, such as what happened yesterday at 10 a.m., or when and how long the pumps ran.
The Florida wastewater facility purchased two 8-channel VDMs and was able to combine multiple paper chart recorders onto the Memo-Graph units.
Following the installation, adequate capacity remained for future expansion and additional applications using the same Memo-Graph units. Data from the system was presented to the state of Florida?s Department of Environmental Protection. State regulators accepted the data from the new package as valid records for the regulated parameters.
Menu-guided text operation and the built-in help function are intended to make operation simpler. Using push buttons, users can select the most applicable signal display including curves, tables, bar graphs, columns, events and groups.
The system can evaluate currents from ? 1 mA to ?- 40 mA, voltages from ?- 50 mV to ? 10 V, thermocouples and RTDs, with 14-bit resolution.
The data analysis is designed to function on a semi-automatic basis. It creates conditions, and actual and previous signal quantities and peaks are listed in tables. It automatically evaluates averages, minimum values and maximum values for analog measurement points, calculates intermediate, daily, monthly and yearly analysis. It also displays counter values, operation times and quantities.
Monitoring of limit conditions is intended to secure quality data, reduce costs and provide security. Instead of rewiring devices to add external components, users can get four limit values per analog channel, totally selectable pre and main alarms, presettable hysteresis, unit internal switch outputs (up to 5 relays + 1 open collector output) are presettable, presettable event text lines and messages that need acknowledgement. With certain settings, short-term peaks can be ignored. The unit can react as a Mono-Master, which means it would be appropriate for small systems using up to 16 analog measurement points. In this case, the Memo-Graph takes on the task of interrogating the individual measurement points without the need for a superior computer system.
Data storage is handled with a ?first in, first out? policy ? if the memory should become full, then the oldest data is overwritten. Data also is being copied to diskette, while a check for faults in the information being copied is carried out. Also, when the data is stored in the ReadWin application on a PC, a check for faults is done. The unit stores up to 450,000 measured values.
