BMadson 27DEC05 - I was wondering if FactorySQL is just like RSSQL or if there is there something more to it? It says on your website that it has bi-directional mode. What does that mean?
shechtman 28DEC05 - It’s funny you would mention the bi-directional mode within the context of your question because that is one of the most significant distinguishing features between FactorySQL and RSSQL.
The bi-directional mode perfectly synchronizes PLC addresses to SQL database data fields. In effect, the SQL database becomes a tag database so you can now control any aspect of your process from the SQL database . This would be the case where you would want to control it from web-pages using HTML or DHTML using PHP, ASP, Coldfusion or if you really want to make it easy on yourself, using FactoryPMI.
There are a many other significant differences between RSSQL and FactorySQL. Actually, there is hardly anything to compare. But I would recommend you read the on-line documentation for FactorySQL under Products->FactorySQL->Documentation->Introduction and if you are familiar with RSSQL already, you will see the differences for yourself.
Does that help?
nathan 28DEC05 - FactorySQL provides drag and drop mappings between the PLC and Database
From the RSSQL manual, “Bidirectional transactions in RSSql usually take data from the control system and call a stored procedure that exercises some logic, and then provides RSSql with output values that can be written back to the control system.” In other words bidirectional in RSSQL seems to mean using going to the PLC to get the data - processing it with stored procedures - then writing it (you choose database OR PLC writeback). It’s “Bidirectional” because one procedure can write to the database, while another procedure can write to the PLC.
In contrast, Bidirectional mode in FactorySQL synchronizes a database field with a PLC tag - both ways. That means that if the PLC changes the value, it will be propagated to the database OR if the database is changed it will be written to the PLC. It’s important for the software package to support this feature natively if you wish to “tie” both sides together, as you could get “continuous bounceback”, or undesired “feedback loops” if you try to set up 2 stored procedures/groups pointing to the same place in opposite directions.
Here’s a mixed environment (Panelview/HMI/Web) example where this is applicable. Suppose you had tags in the PLC representing user controlable setpoints and you use a FactorySQL bidirectional item to map the PLC and DB to each other. A panelview in the field could directly change the tag. FSQL would propagate the change to the database, and web/FactoryPMI users would see the new setpoint. If web/FactoryPMI users change the database value, FSQL would write the new value to the PLC and the factory system/panelview would use the new value as written to the database.
I’d recommend trying FactorySQL. I prefer it to RSSQL because it’s so quick and easy to get going in minutes, not so much because of defincies in specific features. I’ve yet to find a “power user” task that can’t be accomplished with FactorySQL’s more advanced features.