... ,current,phase,frequency,phase sequence,power 2.RS232 ETCR 4000A Double Clamp /Three Phase Digital Phase Meter Features: Simultaneously measure two AC ... Application1. Single-phase test 2. Three-phase four-wire test3. Three-phase three-wire test ETCR4000A Double Clamp /Three Phase Digital Phase Meter ----Manufactory, RS232 ...