Siemens LR200 Quick Start Manual page 24

Allowable operating area
Curve 1 (General Purpose,
Intrinsically Safe, Non-
incendive)
Loop Voltage versus Loop
Resistance
Curve 2 (Flameproof,
Increased Safety, Explosion-
proof)
Loop Voltage versus Loop
Resistance
Startup Curve
Note: At startup, it can take
anywhere from 25 to 55 seconds
for the device to report the actual
material level.
7ML19985XC81
900
800
700
600
(17.8v, 300 ohms)
500
400
300
RL=272.7*VL – 4554.1
200
(16.7v, 0 ohms)
100
0
15
Curve 2: Power Supply Requirements
400
350
300
250
200
(30.0v,845 ohms)
150
100
(16.7v, 0 ohms)
50
0
15
40
35
30
25
20
15
10
5
0
0
SITRANS LR200 (HART) – QUICK START MANUAL
Curve 1: Power Supply Requirements Power Supply Requirements
RL=44.6*VL – 493.4
ALLOWABLE
OPERATING AREA
17 19 21
Loop Voltage – VL
Loop Voltage - V
(Source Voltage)
Power Supply Requirements
RL=44.6*VL – 493.4
(17.8v, 300 ohms)
RL=272.7*VL – 4554.1
ALLOWABLE
OPERATING AREA
20
Loop Voltage – VL
Loop Voltage - V
(Source Voltage)
Loop Power Supply
(no Current Limit)
Loop Power
Supply with 25 mA
Current Limit
5 10 15 20 25 30
Time (seconds)
Time (secs)
No current limit
No Current Limit
(30.0v,845 ohms)
23 25 27 29
L
25 30
L
actual material level
(example value 18 mA)
35 40 45 50 55
Current-limited power
Current Limited Power Supply
Page EN-23