Sequence-of-events modules

The Allen-Bradley 1756-IB16ISOE and 1756-IH16ISOE sequence of events (SOE) modules feature sub-millisecond resolution for first-event detection and sequence of event data capture for event cascades. This makes the integrated ControlLogix SOE modules suitable for substation automation, emergency shutdown systems and applications for which change-of-state data is required.

The modules are available in 24 and 125 V versions, both offering two data-capture modes — ‘coordinated system time per-point’ and ‘first-in/first-out’.

CST mode provides two time-stamps per input point — for on/off and off/on — making it useful for first-fault detection and determining the order of a sequence of transitions.

The modules fit into a ControlLogix rack, expanding the input time-stamping capability of standard input modules, from per-module to per-channel, across 16 channels.

The modules can be deployed in a processing plant in a manner similar to a digital ‘black-box flight recorder’, to determine where things went wrong in the first place.