Vaisala Thunderstorm Electric Field Mill EFM550 integrates with Vaisala local-area, real-time lightning systems to monitor the development and dissipation of overhead lightning threats by measuring the local atmospheric electric field.  EFM550 data can be displayed using optional Vaisala ALARM Automated Lightning Alert Risk Management Software to show current electric field measurements numerically and graphically. The EFM550 integrates with local-area, real-time lightning information systems: Vaisala Thunderstorm Lightning Warning System TWX300 Vaisala Thunderstorm Sensor TSS928 with Vaisala ALARM Automated Lightning Alert Risk Management software

Operational Specifications
Accuracy				+/- 5% of reading offset +/- 50 v/m
Response Time				1 Sec
Signal Interface				8-bit binary digital signal RS-485(RS-422 compatible); full duplex
Sampling				Fixed 2/sec message rate
Range				+/- 10 kV/m, max.
Environmental Conditions
Operating/Storage Temperature Range				-10 °F to +115 °F (-23 °C to +46 °C)
Humidity				0% to 100%
Mechanical
Motor				Brushless; 25,000 hours MTBF
Cable				4-twisted pair, 24 AWG min
Electrical
Voltage				100-240 VAC, 50-60 Hz; or 20-30 VDC
Power Protection				Multi-stage transient protection
Power				Consumption 2.3 watts
Mounting
Hardware included for convenient mounting to a vertical pipe or      flat mounting surface. Minimum 6.0 in.(15.2 cm) clearance from bottom of junction box      to mounting surface. Maintain a minimum of 18.0 in.(45.7 cm) area clear between mill      head and mounting surface.