Built-in 3V CR2450 battery (retains program settings during power outages). Time Error: Less than 2 seconds per day. 2. Terminal Layout and Wiring Diagram
Digital timers use a crystal oscillator. The TM630S has an accuracy of ±1 second per day. If it is losing minutes per week, the internal crystal is failing, or the unit is exposed to extreme temperatures outside of -10°C to 55°C.
