Introduction

This Driver allows communication with BCM programmable controllers via BCM2 Master Slave protocol.

The Driver also offers resources for reading PLC-provided timestamps, using the Reading Absolute Addresses with Timestamp, Sequencing of events (SOE), and Reading Digital Input Events methods.

The first method consists of reading an absolute PLC's memory position containing a queue of blocks, where each block contains, in addition to the values of Elements for the corresponding Block Tag, a linked timestamp. Reading such blocks with a timestamp can be performed by using Block Tags with the B2 parameter equal to 9 (nine).

The sequencing of events (SOE) consists of reading a list of events stored in a circular buffer in the PLC's memory, which must be kept by the PLC software. Such events are generated by the controller inputs, and they must be stored as they occur, each one containing information about its type, the input that generated it, and the moment it occurred (timestamp) relative to a pre-defined time base. Events must be stored even when an application is not executing, up until that application perform their download. The time base is stored in the PLC's memory, so that it is not erased when closing an application, except when an overflow occurs. To read and configure this resource, use PLC Tags with the N2 parameter equal to 999 and Block Tags with the B2 parameter equal to 10.

The method of reading digital input events is commonly used in RTUs (Remote Terminal Units) in substations. To read these events, users must use Block Tags with the B2 parameter equal to 10.

For more information about timestamp features, please check specific topics later in this document.