4.3.9 Sensor Break Safe Output Demand

 

If a sensor break alarm occurs S.br is displayed the output from the controller will adopt a ‘Safe’ level. This is set using ‘P’ code P36. The safe default output is 0% which means that all control outputs are off. For a heat/cool controller the full range is -100% to +100%. It is not limited by the Output High and Low limits set in Operator Level 2. The level set must be chosen with care to make sure that the process does not over heat or over cool. In specific installations it may be useful to maintain a small amount of power to keep the process at a ‘standby’ temperature if the input sensor fails.

 

If the controller is in nAN mode (Auto/Manual = Man) S.br is displayed if a sensor break condition occurs, but the output power does not adopt the ‘Safe’ value but will adopt level set manually.

 

If the controller is in standby mode (Auto/Manual = OFF) S.br will be displayed if a sensor break condition occurs, and the outputs will always go to off (0%).