Each trident system consists of three main processor (MP) modules, each of which is located on a backplane. Each MP module serves as a channel trident system. The communication module and substrate communication module (CM) are MPs with a three E-to-one interface that allow the use of industry standard communication protocols- A single trident controller can support up to two CMs operating independently on one CM backplane. Two CMs can provide redundant communication connections or independent communication ports. Please refer to page 27 for details. The analog input module and substrate each have three independent channels for processing analog input devices from the field. Each channel transmits data to the MP associated with the channel. Members of parliament vote on the data to the application before passing it. Each TMR digital output module has three sets of isolated electronic devices called channels, which independently receive data from the MP associated with each channel. These channels use patented four channel voting circuits to vote on a single output signal applied to the load. This voter circuit is based on a parallel series path, and if two of the three switches (channels A and B, or channels B and C, or channels A and C) command them to close, these paths will transmit power. The quadruple voting circuit has multiple redundancy on all critical signal paths, ensuring safety and maximum availability. For each point, the DO module periodically executes the Output Voter Diagnostic (OVD) program. In order to allow unrestricted safe operation in various multi fault situations, OVD detects and alarms these types of faults: all faults stuck in the on and off positions are detected within less than 500 milliseconds. Switch 1 detects all switches or their related drive circuits that are stuck in the on or off position. The DO module includes complete and continuous diagnostics for each channel. If the diagnostic program detects a fault on any channel, the fault indicator light will light up and activate the system alarm. The fault indicator identifies a channel fault, rather than an entire module fault. The DO module ensures normal operation in the event of a single fault and can continue to operate normally in the event of certain multiple faults. Does the module support hot spare modules. Each DO module is fixed with mechanical keys to prevent improper installation in the configured substrate.