摘要 |
Wheel type electronic sheet material area measuring machine has means arranged to emit a test start signal, which may be manually operated or automatically operated at a particular stage in the machine cycle, and test means actuated by the signal which cause all of the detecting means of the machine to emit a signal normally indicating presence of sheet material for a predetermined period of such a length that, in the normal operation of the machine, the signalling means of each wheel should generate at least one pulse. Should a pulse not be received from one of the wheels in the allowed time, a signal is given indicating that the machine is faulty. The invention includes means to indicate which of the arm and wheel assemblies is faulty.
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