BTM-055-20 Finisar Corporation., BTM-055-20 Datasheet - Page 7

• Manufacturer Part Number: BTM-055-20
• Description: Rohs Bantam Trapezoidal Torque Amplifer Module
• Manufacturer: Finisar Corporation.

PWM LiMiTinG inPUT
i2t limit settings
about pwm limiting
PWM limiting sets a maximum value for the on vs. off time of the outputs of the amplifier. While the peak voltage seen by the load
remains about the same as the supply voltage (HV), the average voltage seen by the motor can be limited.
A common use of this is to limit the maximum RPM of a motor even though it’s operating in torque mode.
pwm limit settings
Copley Controls, 20 Dan Road, Canton, MA 02021, USA
Web: www.copleycontrols.com
100
90
80
70
60
50
40
30
20
10
97
78
70
68
62
57
45
38
28
25
25
%
%
Rset (K)
<OUT>
4.50
4.00
3.50
3.00
2.50
2.00
1.50
1.00
0.50
Vi2t
5.0
7.5
2.5
42
30
25
20
15
10
5
0
<OUT>
90000
40000
23333
15000
10000
6667
4286
2500
1111
Vset
4.95
4.00
3.71
3.54
2.97
2.48
2.12
1.65
0.99
Ri2t
3.3
0
Bantam
Vi2t
Vcont
Ri2t
Rcont
equivalent circuit
equivalent circuit
J1-2
J1-6
Control
+5 V
+4.87 V
Control
I2T
Icont
10000
9799
I2T
Vcont
Trapezoidal Torque
Amplifier Module
Tel: [phone]
example i2t setting
if a voltage Vpeak is used to control the i2T,
Vi2t = 5.0 * I2TSecs
Example: find Vi2t for a 6 A PeakLimitCurrent
Vpeak = 4.80 * 6 = 1.44 V
To use a resistor for setting Peak-Limit current,
Rpeak =
Example: find Rpeak for a 14 A PeakLimitCurrent:
Rpeak =
example pwm setting
The table shows duty cycles measured with some
it can be found like this:
using a BTM-090-20:
calculate the value as follows:
choices of Rset for the PWM limits.
Ampi2TLimit
(AmpPeakCurrent - PeakLimitCurrent)
20
9600 * PeakLimitCurrent
9600 * 14
(20 - 14)
= 22,400 ohms
Fax: [phone]
RoHS
Page 7 of 18