Remote monitoring systems are most valuable when they provide accurate and timely data to the user. Even the best visualization and analysis tools are useless if the source data is missing or incorrect. In computer science, this is known as "garbage in, garbage out". Data quality breakdown can happen when communication paths are unreliable, when sensors fail, or when batteries die. Data gaps or inaccurate readings are almost a certainty when these failures occur. Graphs can become choppy or unreadable. Erroneous alarm notifications, both false positives and false negatives, will likely occur. Fortunately, there are steps that can be taken to improve SCADA data quality.
Improve communication path reliability
Cellular modems are a popular choice for connectivity between the monitored location and the SCADA host. In some rural areas, cellular service can be unreliable. Reliability can be improved by using a SIM that supports multiple carriers or by installing a secondary cellular modem. A broadband satellite connection can be reliable and is often used to supplement or replace the cellular link.
For locations with only solar power, it is important to correctly size the battery and solar panel. Meter equipment commonly terminates power to the communication equipment when forced to enter a low-power state. The meter may continue to run and log production, but real-time data collection from the meter halts. Choosing the correct low-power cellular modem can also make a large difference when experiencing power issues.
Utilize on-site logging to keep data consistent and clean
Electronic flow meters (EFMs) typically have 35+ days’ worth of internal archive storage to meet AGA requirements. Your SCADA system should take advantage of this. Syncing an archive rather than just logging live readings allows you to have gapless data even if the communication path to the meter is unreliable. On-site logging can also be used for things other than meter data, including external pressures, tank levels, etc.
Use alarming to detect and resolve issues promptly
Alarms should be configured to quickly detect and report issues of data quality. Communication failure alarms are easy to configure and can report directly to field technicians when communication is down longer than a configurable tolerance. More complex alarms can also be configured to detect issues like frozen sensor value, negative pressures, and low battery.
Use a SCADA host with a proven track record of high availability.
All steps taken on the field side to improve reliability must be paired with a reliable SCADA hosting service to ensure end-to-end reliability. The SCADA host going down for even a small amount of time can be catastrophic to data quality. At zdSCADA, we take pride in building a redundant and reliable SCADA hosting solution. With today’s advancement in cloud hosting infrastructure, greater than 99.9% uptime on the SCADA application is easily attainable. If you are settling for less than that, please contact zdSCADA for a free consultation.