The MicroNet™ Safety Module is a safety PLC with integrated overspeed and over-acceleration protection designed to safely shut down any steam, gas, or hydro turbine upon sensing a safety event. Available with two dual-redundant trip relay outputs using 2-out-of-3 voted architecture, or with three independent non-voted trip relay outputs. The MicroNet Safety Module is designed to be applied as part of a MicroNet control system. This ProTech MSM model is a panel mount, high voltage/low voltage power input, independent relays/voted inputs with math function safety device for steam turbine overspeed protection.
The MSM functions as a safety PLC, as it accepts 10 discrete or analog inputs per module (30 total), and allows users to create custom safety/protection programs to safely protect site personnel and equipment. Programmers are able to utilize typical logic and testing sequence routines to create their application-specific safety logic and tests.
Each MSM module can be tested manually from the module’s front panel, Modbus communications port, or automatically via its auto-test routine function. The MSM allows users to configure overspeed or custom-programmed tests to be performed manually or automatically on a periodic basis. With these test routines, each module (A, B, C) is tested one at a time, and either a successful test result is logged or, upon sensing a fault, the routine is halted and the sensed fault indicated/alarmed.
The MSM’s triple modular design allows users to easily replace one of its modules (A, B, C) while the monitored equipment/turbine is on-line and operating normally. Ease of replacement is enhanced by the unit’s backplane plug-and-operate structure, and its module-to-module learning function.
Trip, Alarm, & Overspeed Logs
The MSM log function logs (saves to memory) all trips, alarms, trip valve response times, and overspeed events. The trip log function uses a scrolling buffer and records the last 50 sensed trip or alarm events and the last 20 overspeed events to memory, with associated times. Each log file can be viewed from the unit’s front panel, or downloaded to a computer via the MSM service tool program. Each module utilizes nonvolatile memory to ensure that all logged events are saved, even on loss of power.
Real Time Clock
Each MSM module utilizes a real-time-clock to ensure accurate time logging. A special time averaging function is utilized between modules to ensure module-to-module clock synchronization. Alternatively one of the MSM’s inputs can be configured to accept a discrete clock synchronization input signal from a plant DCS or other time synch device.
PROTECTING YOUR ASSETS--SAFETY SYSTEMS FOR TURBINES AND COMPRESSORS