The 7922 and 7932 use an EEPROM to store the programme settings and count values. This is achieved by monitoring the meter’s internal power supply.
If the external supply voltage is switched off, the internal voltage drops accordingly; this is detected by a special circuit and the safeguard mechanisms are activated, ensuring that all relevant data is saved to the non-volatile memory. In addition, a so-called „checksum“ is generated, which is also stored in the memory.
When the external power supply is switched on again, the processor reads the data from memory, generates a checksum and compares it with the one stored. If the new checksum differs from the one previously stored, the processor interprets this as an error and assumes that a data error has occurred. This results in the message „ERR CH“, which indicates a data error.
This fault may be caused by a fault in the processor, the EEPROM, or by external voltage spikes. If the fault is caused by external voltage spikes, this can be prevented by using suitable filters. A “power-up reset” is required to rectify this fault.

1. Switch off the power supply.
2. Press the PROG button and the digit 5 button at the same time and hold them down.
3. Switch the power supply back on whilst holding down the buttons. Hold the buttons down for approx. 15 seconds until 7922/7932 appears on the display.
4. The EEPROM memory has now been reset to its default values and the counter must be reprogrammed.