Combustion controlling device and combustion system

Abstract

A determination precision of an abnormality detection element such as an interlock is improved using a combustion controlling device that includes an output circuit that supplies a binary output signal to one contact of an abnormality detection element, an input circuit that generates a binary input signal corresponding to a signal output from another contact of the abnormality detection element, a sampling portion that samples the input signal within a first period and a second period in which the output signal is respectively a first logic level and a second logic level, an abnormality detection element state determining portion that determines the state of the object to be monitored on the basis of a sampling result in the first period, and a circuit failure determining portion that determines whether a failure occurs in the output circuit and the input circuit on the basis of a sampling result in the second period.

1 . A combustion controlling device, comprising:
 an output circuit configured to supply a binary output signal to one of two contacts of an abnormality detection element that is in a short-circuit state or an open state between the two contacts according to a state of an object to be monitored;   an input circuit configured to receive a signal output from the other contact of the abnormality detection element to which the output signal is supplied, the input circuit configured to generate a binary input signal corresponding to a logic level of the input signal;   a sampling portion configured to sample the input signal within a first period in which the output signal is a first logic level, and samples the input signal within a second period in which the output signal is a second logic level;   an abnormality detection element state determining portion configured to determine the state of the object to be monitored by the abnormality detection element on the basis of a sampling result in the first period by the sampling portion; and   a circuit failure determining portion configured to determine whether a failure occurs in the output circuit and the input circuit, or not, on the basis of a sampling result in the second period by the sampling portion.   
     
     
         2 . The combustion controlling device according to  claim 1 , wherein
 the abnormality detection element state determining portion is configured to determine that the object to be monitored by the abnormality detection element is normal when it is detected that the logic level of the signal input to the input circuit in the first period is the first logic level N times in a row with reference to sampling values in the first period for successive N (N is an integer of two or more) times, and the abnormality detection element state determining portion is configured to determine that the object to be monitored by the abnormality detection element is abnormal when it is detected that the logic level of the signal input to the input circuit in the first period is the second logic level N times in a row.   
     
     
         3 . The combustion controlling device according to  claim 2 , wherein
 the circuit failure determining portion is configured to determine that at least one of the output circuit and the input circuit fails when it is detected that the logic level of the signal input to the input circuit in the second period is the second logic level M times in a row with reference to sampling values in the second period for successive M (M is an integer of two or more) times.   
     
     
         4 . The combustion controlling device according to  claim 3 , wherein
   M≧N.
   
     
     
         5 . The combustion controlling device according to  claim 1 , wherein
 the sampling portion performs sampling in the first period after a first time period elapses since the output signal switches from the second logic level to the first logic level.   
     
     
         6 . The combustion controlling device according to  claim 5 , wherein
 the sampling portion performs sampling in the second period after a second time period elapses since the output signal switches from the first logic level to the second logic level.   
     
     
         7 . The combustion controlling device according to  claim 6 , wherein
 the first time period is less than the second time period.   
     
     
         8 . The combustion controlling device according to  claim 1 , wherein
 a plurality of sets of function blocks including the sampling portion, the abnormality detection element state determining portion, and the circuit failure determining portion are provided, and   the respective function blocks are configured by a plurality of different program processing devices, individually.   
     
     
         9 . The combustion controlling device according to  claim 1 , further comprising
 a controlling portion configured to control the operation of a burner on the basis of determination results of the abnormality detection element state determining portion and the circuit failure determining portion.   
     
     
         10 . A combustion system, comprising:
 the combustion controlling device according to  claim 9 ; and   the burner that is disposed in a combustion chamber and controlled by the combustion controlling device.