| 摘要 |
<p>An improved gas meter comprises an optical transmitter that outputs an optical signal in response to an output from a gas meter counter. A pickup device is provided which includes an optical receiver arranged to receive the optical signal sent by the transmitter. The pickup device includes isolation circuitry required to detect the optical signal and provide a volt free (or zero volt) replicated pulse to a downstream or external device. The isolation circuit may be an electrical relay, a transformer coupling or an optical isolator. The pickup device is removably attached to the outside of a meter or a logger and so does not need to be intrinsically safety approved.</p> |
