Connecting FieldPoint module to Lookout 4.51 through Ethernet

[SYCO]

When connecting FieldPoint modules to Lookout 4.51 through an Ethernet link, what are the advantages and disavantages of the 3 different ways of doing that : Logos networking, Lookout OPC Client object class, Lookout FieldPoint object class connection.

[Aaron_G]

There are several things to consider when choosing which method that you use for communications between Lookout and FieldPoint. Ultimately, the choice comes down to your specific needs. Since it is not easy to create a table to list the differences on Developer Exchange, I will create a list of issues with each method.

Issue 1, Communication Compatibility: Using the Logos networking option, you are unable to switch between FieldPoint Ethernet Network Modules and Serial Network Modules. Using both the OPC and FieldPoint.cbx methods, it is fairly trivial to do so.

Issue 2, Module Compatibility: FieldPoint network modules and the FieldPoint OPC Server have the ability to learn new I/O modules as they release (with very few exceptions that require firmware and/or FieldPoint Explorer upgrades), however, the FieldPoint.cbx does not have this ability and can sometimes not support new modules for several months.

Issue 3, Dial-up support: Currently, only the FieldPoint.cbx supports the ability to use dial-up (modems) for FieldPoint Serial network modules.

Issue 4, Error Information: For different reasons such asloss of power to FieldPoint bank, error messages may be returned. In addition, some modules support channel specific error messages (e.g. Open RTD on the FP-RTD-122 or Out of Range on the FP-AI-110). This information will be displayed exactly using the FieldPoint.cbx. The FieldPoint OPC Server makes this information available using a technique known as the Get Error String method for OPC. Lookout 4.5 and prior (I do not know about 4.51) do not suppot the Get Error String methodolgy so all errors are displayed as "Bad Data from OPC Server: Non Specific Error". Generally, using the direct link, will display the specific error reason and not a generic.

Issue 5, Configuration: Using the FieldPoint.cbx and the FieldPoint OPC Server, you have the ability to read/write data to an I/O point and to change it's attributes (e.g. filter setting), however, you can not change the range of the I/O point (e.g. 0 - 5 Volts vs 0 - 10 Volts). Using the Logos networking option, you can change the range of an I/O point.

Issue 6, Logging Data: Using the FieldPoint.cbx or the OPC Client, you are directly able to configure any I/O point to be logged to Citadel. Using the Logos networking, you would need to create an expression object for each data point that you want to log and enable logging on each expression object.

Generally speaking, I recommend the FieldPoint.cbx for users needing dial-up ability, the Logos networking option for users needing the ability to dynamically change the range of a channel, and the FieldPoint OPC Server for all other situations.

Regards,
Aaron

[SYCO]

Thanks for this informative answer.