Emerson ROC827 instruction manual Issued Mar-06 General Information

ROC827 Instruction Manual

ƒHistorical Database.

ƒEvent and Alarm Log Databases.

ƒApplications (PID, AGA, FST, and such).

ƒMeasurement Station Support.

ƒDetermining Task Execution.

ƒReal-Time Clock.

ƒEstablishing and Managing Communications.

ƒSelf-Test Capability.

The firmware makes extensive use of configuration parameters, which you configure using ROCLINK 800 software.

RTOS The ROC800-Series firmware uses a pre-emptive, multi-tasking, message-based Real-Time Operating System (RTOS) with hardware- supported memory protection. Tasks are assigned priorities and, at any given time, the operating system determines which task will run. For instance, if a lower priority task is executing and a higher priority task needs to run, the operating system suspends the lower priority task, allows the higher priority task to run to completion, then resumes the lower priority task’s execution. This is more efficient than a “time sliced” architecture type.

TLP The ROC827 reads data from and writes data to data structures called “points.” A “point” is a ROC Plus Protocol term for a grouping of individual parameters (such as information about an I/O channel) or some other function (such as a flow calculation). Points are defined by a collection of parameters and have a numerical designation that defines the type of point (for example, point type 101 refers to a Discrete Input and point type 103 refers to an Analog Input).

The logical number indicates the physical location for the I/O or the logical instance for non-I/O points within the ROC827. Parameters are individual pieces of data that relate to the point type. For instance, the raw A/D value and the low scaling value are parameters associated with the Analog Input point type, 103. The point type attributes define the database point to be one of the possible types of points available to the system.

Together, these three components—the type (T), the logical (L), and the parameters (P)—can be used to identify specific pieces of data that reside in a ROC827’s data base. Collectively, this three-component address is often called a “TLP.”

I/O Database The Input/Output database contains the input and output points the operating system firmware supports, including the System Analog Inputs, Multi-Variable Sensor (MVS) inputs, and Input/Output (I/O) modules. The firmware automatically determines the point type and point number location of each installed I/O module. It then assigns each input and output to a point in the database and includes user- defined configuration parameters for assigning values, statuses, or identifiers. The firmware scans each input, placing the values into the

Issued Mar-06 General Information 1-9