Smith-Root LR-20 Series, User Manual, Page: 25 / 28

Use this chart to convert settings used with the 12-B or 15-D to settings on the LR-20.
APPENDIX A: MODEL 12-B/15-D SETTING CHART
DUTY CYCLE PERCENT LR-20/LR-20B
Frequency 5 10 15 20 25 30 35 40 45 50 60 70 80 GB 2 Pulse GB 3 Pulse
10
5ms 10ms 15ms 20ms 25ms 30ms 35ms 40ms 45ms 50ms 60ms 70ms 80ms 4Hz 4Hz
15 3.3ms 6.7ms 10ms 13.3ms 16.7ms 20ms 23.3ms 26.7ms 30ms 33.3ms 40ms 46.7ms 53.3ms 62.5ms 62.5ms
20 2.5ms 5ms 7.5ms 10ms 12.5ms 15ms 17.5ms 20ms 22.5ms 25ms 30ms 35ms 40ms @ 1Hz rate @ 1Hz rate
25 2ms 4ms 6ms 8ms 10ms 12ms 14ms 16ms 18ms 20ms 22ms 24ms 26ms 125ms 187.5ms
30 1.7ms 3.3ms 5ms 6.7ms 8.3ms 10ms 11.7ms 13.3ms 15ms 16.7ms 20ms 23.3ms 26.7ms 12.50%
Overall Duty
Cycle
18.75%
Overall Duty
Cycle 35 1.4ms 2.9ms 4.3ms 5.7ms 7.1ms 8.6ms 10ms 11.4ms 12.9ms 14.3ms 17.1ms 20ms 22.9ms
40 1.3ms 2.5ms 3.7ms 5ms 6.2ms 7.5ms 8.7ms 10ms 11.3ms 12.5ms 15ms 17.5ms 20ms
45 1.1ms 2.2ms 3.3ms 4.4ms 5.6ms 6.7ms 7.8ms 8.9ms 10ms 11.1ms 13.3ms 15.6ms 17.8ms
50
1ms 2ms 3ms 4ms 5ms 6ms 7ms 8ms 9ms 10ms 12ms 14ms 16ms
60 0.8ms 1.7ms 2.5ms 3.3ms 4.2ms 5ms 5.8ms 6.7ms 7.5ms 8.3ms 10ms 11.7ms 13.3ms
70 0.7ms 1.4ms 2.1ms 2.9ms 3.6ms 4.3ms 5ms 5.7ms 6.4ms 7.1ms 8.6ms 10ms 11.4ms
80
0.6ms 1.3ms 1.9ms 2.5ms 3.1ms 3.8ms 4.4ms 5ms 5.6ms 6.3ms 7.5ms 8.8ms 10ms
90 0.6ms 1.1ms 1.7ms 2.2ms 2.8ms 3.3ms 3.9ms 4.4ms 5ms 5.6ms 6.7ms 7.8ms 8.9ms
100 0.5ms 1ms 1.5ms 2ms 2.5ms 3ms 3.5ms 4ms 4.5ms 5ms 6ms 7ms 8ms
110 0.5ms 0.9ms 1.4ms 1.8ms 2.3ms 2.7ms 3.2ms 3.6ms 4.1ms 4.6ms 5.5ms 6.4ms 7.3ms
120 0.4ms 0.8ms 1.3ms 1.7ms 2.1ms 2.5ms 2.9ms 3.3ms 3.8ms 4.2ms 5ms 5.8ms 6.7ms
STANDARD PULSES MODEL 12-B AND 15-D
Mode Switch 1 2 3 4 5 6
A
1Hz 2ms 3ms 4ms 6ms 7ms 8ms
B 5Hz 1ms 2ms 3ms 4ms 6ms 8ms
C 10Hz 500us 1ms 2ms 4ms 6ms 8ms
D
15Hz 500us 1ms 2ms 4ms 6ms 8ms
E 20Hz 500us 1ms 2ms 4ms 6ms 8ms
F 30Hz 500us 1ms 2ms 4ms 6ms 8ms
G
40Hz 500us 1ms 2ms 4ms 6ms 8ms
H 50Hz 500us 1ms 2ms 4ms 6ms 8ms
I 60Hz 500us 1ms 2ms 4ms 6ms 8ms
J
70Hz 500us 1ms 2ms 4ms 6ms 8ms
K 80Hz 500us 1ms 2ms 4ms 6ms 8ms
L 90Hz 500us 1ms 2ms 4ms 6ms 8ms
M
100Hz 100us 500us 1ms 2ms 4ms 6ms
N 110Hz 100us 500us 1ms 2ms 4ms 6ms
O 120Hz 100us 500us 1ms 2ms 3ms 4ms
Example
: If H2 were used with the model 12-B, the corresponding settings for the LR-20
would be 50Hz at 5% Duty cycle. Note that the LR-20 does not have pulse width settings.
See diagrams at left for an explanation of
Duty Cycle , Output Frequency and Gated Bursts .
PERIOD
DUTY
CYCLE
V
O
L
T
S
FREQUENCY
PULSE
WIDTH
Pulse width x Frequency x 100 = Duty Cycle in %
V
O
L
T
S
Duty cycle and Output Frequency
Gated Burst
Frequency
1
Period
=
Time
Width
Burst = 3 pulses
Period
Burst rate
Between
Volts
Volts
Time
Width
Period
Gated burst
Standard pulse
1
Period
=
USER’S GUIDE
23 2018