| 摘要 |
<p>PURPOSE:To achieve diagnosis of short of a light receiving element in a simple construction by providing light source control means for turning on and off a light source, when there is no article to be conveyed, and control means for comparing signals of the light receiving element in response to on-off action of the light source. CONSTITUTION:Prior to counting of bills, self diagnosis of a photoelectric sensor 17 is carried out. First, a CPU 6 transmits a signal to turn on a switch 16 and detects whether a signal from a light receiving element 4 is received. Then, it transmits a signal to turn off the switch 16 and detects whether a signal from a light receiving element 4 is received. Thus, the CPU 6 compares the signals transmitted to the switch 16 and the signals from the light receiving element 4 to check the photoelectric sensor 17, and if there is any abnormality, it transmits an abnormal signal. Such a check is repeated at intervals of a predetermined number of bills to obtain early detection of detection error.</p> |
