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Pods - PD2 |
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Overview of the PD2
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Voltage Monitoring The mains voltage is measured as full
wave rectified RMS level with most of the ac component removed by a high
pass filter. The signal is then peak limited, potted down to set the
nominal voltage for 230 volts ac and high frequency filtered to remove
unwanted noise. 4 voltage measurements are taken and averaged each half
cycle of the mains. The result is used to determine the voltage status
of the mains input every 20mS, or half mains cycle.
The PD2 is connected to the LV network via a fused plug fitted with a 3A fuse. This allows easy connection to the domestic electricity supply. The cable is fed through a rear panel mounted gland on the PD2 and soldered directly onto the POD PCB (connections are labelled L{ive}, N{eutral}, E{arth}). The input voltage to the LV approved transformer is fed through a 3A (quick blow) glass fuse and filtered by X-Y capacitors, to remove unwanted fast transients from the supply and prevent harmonics from being fed back into the supply. Event Detection and Reporting All events are date and time stamped locally within the PD2, the internal real-time clock is synchronised with the Host Station clock during every contact. Event Logs are stored in non-volatile memory (EEPROM). The following events are logged by the PD2:
All events are logged with the date and time of the event and up to 7 timers to describe the profile of the event. Most events produce immediate communication with the Host Station, however the PD2 can store up to 10 events prior to automatic download. Communication Event logs are communicated to the Host Station over a standard PSTN
2-wire extension line circuit. A V22 line modem is used to communicate
with the PC based Host Station. Using the V22 standard ensures that the
POD can exchange data with almost any proprietary modem installed
throughout the world. Click here to go back to the main POD page::
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