HZSF-702 is equipped with a large capacity rechargeable lithium battery, which can work continuously for more than 10 hours after being fully charged, covering the on-site testing needs of one working day. But the manual has a clear reminder: the charging power cord must be unplugged during measurement. This requirement is not written casually, there are specific technical reasons behind it.

Why is the measurement on the high side when charging

When charging, 220V AC power is converted into DC power through the internal charging circuit of the instrument to charge the battery. This process will introduce certain electromagnetic interference (mainly high-frequency ripple of the switching power supply) in the internal circuit of the instrument, which may affect the signal acquisition of micro current level sensors, resulting in unstable or high dew point readings.

For dry SF6 gas with a micro water content as low as tens of ppm, this level of interference may result in significant errors when added to the measurement signal. The direct suggestion given in the manual is to unplug the charging power cord during measurement and use pure DC power (with built-in battery) to ensure measurement accuracy.

Electricity management

The real-time battery level is displayed in the upper right corner of the HZSF-702 color screen. When the battery level indicator turns red, it indicates that charging is required. It should be turned off in a timely manner before continuing to use.

The charging operation is very simple: connect the power cord to a 220V socket, and the instrument will automatically charge without turning on the power switch. The charging time usually takes more than 10 hours.

Preparation before going out for testing

The safest arrangement is to connect the charging cable and fully charge it one night before planning to go out for testing. After being fully charged, the 10 hour battery life is sufficient for most on-site inspection tasks. If the daily detection task is too long, you can carry a charging cable with you and briefly replenish the battery during the intermittent movement between devices, but remember to unplug the cable when measuring.