Installation Instructions

Micropilot FMR20 Modbus RS485
Endress+Hauser 11
Continuous measuring mode switched on/off via RTU
A
A
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
1
39
33
8
t
P
C
D
(mW)
(s)
3
A0038153
 5 Power consumption of continuous measuring mode switched on/off via RTU
A Start-up
B Measurement
C Switch on power supply
D Switch off power supply
Calculation example
Assumed configuration
• RTU: E+H FXA30B with battery (7.2 V, 14.5 Ah)
• Modbus: single-shot mode switched on/off via RTU
• Switch on power supply every 15 min and leave switched on for 30 s
Power consumption with Vcc = 7.2 V
• Start-up: 33 mW + (7.2 V - 24 V) × 0.28 = 28.3 mW
• Measurement: 39 mW + (7.2 V - 24 V) × 0.28 = 34.3 mW
• Power save mode: 30 mW + (7.2 V - 24 V) × 0.28 = 25.3 mW
Energy of a measurement:
E= 8 s × 28.3 mW + 3 s × 34.3 mW + (30 s - 8 s - 3 s) × 25.3 mW = 810 mWs
Number of measurements:
7.2 V × 14.5 Ah × 3 600 / 0.810 Ws = ~ 460 000 measurements
Operating life:
460 000 × 15 min = 4 790 days = 13 years
The energy consumption of the RTU is not taken into consideration!
Starting time
Until the 1st measured value:
• 11 s (typically)
• 15 s (maximum)
Until full accuracy:
• 15 s (typically)
• 20 s (maximum)
Power supply failure
The configuration remains stored in the sensor.
Connecting the device Block circuit diagram for Modbus RS485 connection
The RS485 connection meets the requirements of the RS485-IS specification for use in hazardous
environments.