Online monitoring of grounding resistance, grounding voltage. 1. Model No.: ETCR2900B 2. Ground resistance :0.01Ω~2000Ω 3. Communication method :RS485 or GPRS 4. Monitoring Interval Time :Setting range of automatic monitoring interval time :1-999 h 5. Measurement rate:over 10000 times 6. Power Supply : Standard:12V - 24V (±1VDC)、400mA Max(provided externally)