RTConnect

Allen-Bradley PLC HISTORIAN Frequently asked Questions

Configuration is browser-based and follows a few simple steps: discover A-B PLCs, discover or enter tags, normalize and scale those tags, create a data model and define a publishing trigger.

By default, any user can configure the PLC Historian. A configured admin can restrict non-admin users from editing specific configuration settings.

Within the Historian’s browser-based configuration, navigate to the System Settings page and export the configuration of the Historian.

Within the Historian’s browser-based configuration, navigate to the System Settings page and import a previously saved configuration to the Historian.

Time-series data is stored in an InfluxDB database. InfluxDB is a NoSQL, time-series database optimized for storing, querying and analyzing time-stamped data.

There are three storage options: 128 GB, 512 GB or 1 TB.
Example: 100 data points stored every 25 ms produces 85.96 MB/hr.
Example: 10000 data points stored every 5000 ms produces 76.14 MB/hr.

A record size can be calculated with the follow equation:
Number of 8 Bit Values + Number of 16Bit Values * 2 + Number of 32 Bit Values * 4 + Number of 64 Bit Values *8 + Number Strings * 82 + 132 / (Seconds per Record)

Example: ((1) + (2*2) + (4*4) + (7*8) + (1*82) + 132) / 10 = 29.8 bytes per second

When storage fills up, the Historian removes data that has exceeded its assigned retention limits to free space. If no data qualifies for removal, data collection stops. Users set retention limits (in days) for each data model.

The unit displays it on the main page, triggers email alerts at defined thresholds (like 90% capacity) and shows a full storage warning when collection stops.

Data can be exported: physically via USB (CSV/PDF), transmitted over network protocols (MQTT, HTTP, FTP, WebSockets), direct SQL database transfer or manual download through the browser configurator.

Purchases can be made through authorized RTA distributors or directly from Real Time Automation. Purchase orders can be emailed to orders@rtautomation.com or a purchase can be made online at www.rtautomation.com/product/allen-bradley-plc-historian/.

There are no recurring software licenses or subscription fees.

The RTConnect A-B PLC Historian is delivered with a five-year warranty.

All RTA products are delivered with a 30-day return policy. If for any reason you are not 100% satisfied; an application falls through, you find an alternative, you just wanted to give our Historian a try – you can return the unit within 30 days of purchase for a full refund of the purchase price.

Support is available from 8am to 5pm CST. Call 800-249-1612 or email support@rtautomation.com.

Standard technical support is included at no additional charge.

The RTConnect A-B PLC Historian uses either NTP (Network Time Protocol) or a built-in RTC for timestamping. You can configure it as an NTP Client to sync with a time server or users can directly set the time using the real-time clock.

5.28″ (depth) x 4.04″ (height) x 1.5″ (width)

The RTConnect A-B PLC Historian can connect to an unlimited number of Allen-Bradley PLCs . The practical number depends on your total tag count, scan rates, network bandwidth and PLC performance.

In typical installations, the RTConnect A-B PLC Historian can ingest tags from a single Allen-Bradley PLC at intervals as fast as approximately 2 milliseconds under optimal network and PLC loading conditions.

The unit operates 12-24 VDC. Two to three amps are typical.

Multiple RTConnect A-B PLC Historians can be time-synchronized by configuring each unit as an NTP client to a common upstream NTP time server. This ensures that all Historians align their internal clocks to the same authoritative source for consistent timestamping of collected data.

The RTConnect A-B PLC Historian is designed to be mounted in cabinet on a DIN rail.

The RTConnect A-B PLC Historian supports hierarchical user-defined data models. A data model is simply a collection of tags from one or more PLCs in some hierarchical relationship. Data models define how data is grouped for storage, publishing and downstream consumption. Once users select tags from A-B PLCs, those tags can be assigned to any of the previously defined data models.

Previously stored records are not altered, reprocessed or restructured when the data model is changed.

Yes, you can use meta data to add context to your data points. Meta data includes items such as identification values, semantic names, engineering units and measurement context. Metadata is stored with the tag definition and published with time-series records.

Yes, the RTConnect A-B PLC Historian allows users to map data models to ISA-95 level concepts for organizational purposes.

Users can create different kinds of triggers to signal when the Historian should publish data. A typical trigger publishes data at the end of a job. An end of job trigger is based on a control tag. Triggers can also be created to publish data every minute, every hour, at end of day, end of week or end of month.

Yes, the RTConnect A-B PLC Historian can be configured to publish data on a cyclic schedule using time-based triggers. Typical cyclic publishing intervals depend on PLC performance, network conditions, tag count and system load.

Time-series data can be published over MQTT, HTTP, Email attachments, FTP, WebSockets and SQL. Additionally, USB can be used for exporting CSV files to other applications.

A CSV file can be exported from the unit and transferred to Excel using FTP or by transferring the CSV file using a USB flash drive.

The RTConnect A-B PLC Historian supports transfer of data models to SQL database tables in an external SQL database. Records are transferred as published data into external SQL tables. This is not a transactional, storage-engine-level replication. Each row of the InfluxDB table forms a record in a new table or an existing table.

The RTConnect A-B PLC Historian supports admin and user role access using passwords. The admin controls if a user has full access, view access or no access to specific browser-based configuration pages.

The RTConnect A-B PLC Historian supports both HTTP and HTTPS for the browser-based configuration. The admin can enable the configuration for either HTTP or HTTPS that all users of the Historian shall use.

The RTConnect A-B PLC Historian supports unsecure and secure publishing for MQTT(S), SQL with TLS/SSL, FTP(S), HTTP(S) and WebSockets Secure or Email. The browser-based configuration allows users to enable the publisher to be unsecure or secure.