Overview
AMOT Safety Control Systems can be designed to comply with many challenging environments,both technical and physical,from a pneumatic system through electro-mechanical relay to software based programmable types complying with the latest international standards.
- Fail Safe PLC
A Fail Safe PLC System designed using a “failsafe” PLC, where the inputs and outputs are monitored for their actions and the software configuration is compiled such that a fault occurring changes to a predetermined state.
- Redundant PLC
Here a redundant PLC is used where high availability is important,such as in a fire and gas monitoring system. Each input has two sensors wired independently of each other in separate cables taking different routes. In this case the system is “energize to close” (opposite to normal failsafe philosophy), so a break in circuit would not prevent the operation of warning signals on fire pump controllers.
- Triple Modular Redundant (TMR) Plc
Triple Modular Redundant (TMR) Systems are often used where a machine or particular process has a high availability requirement and spuriously sensed fault conditions can create a serious condition or leave the process in a situation where it creates a costly shutdown. Here the PLC receives three independent signals from each of the monitored conditions. They are arranged so the system has a 2oo3 voting on the conditions, for improved reliability.
- General
With all safety systems certain aspects must be considered:
Possibility of a fault
Consequence of the fault recurring
Human intervention (desired or not)
Economics of monitoring and control
Economics of a process failure
Environmental impact
Implementation of relevant standards:
IEC 61508 IEC 61511
IEC 61131 IEC 61132