GE VersaMax, Manual

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13-16 VersaMax® Modules, Power Supplies, and Carriers User's Manual – March 2003 GFK-1504K
13
IC200MDD841
Mixed Module, 24VDC Positive Logic Input 20 Points / Output 12 Point /
(4) High Speed Counter, PWM, or Pulse Train Configurable Points
PWM Outputs
PWM outputs can be used to control DC and stepper motors. The parameters of PWM
output operation are set up using the module’s output data. (See “Module Data”). The
frequency of each PWM output can be set in the range of 22Hz to 2KHz. The % Duty
Cycle of each PWM output can be set from 1 to 100 depending on the frequency of the
PWM output. The graph below plots the relationship between the minimum % Duty Cycle
of a PWM output versus the frequency of that PWM output. Note that this relationship is
based on a default Optical Isolator Correction factor value of 75 μ S. (See “Optical Isolator
Correction Factor” on the next page). For some frequencies, this Optical Isolator
Correction factor may be changed to further decrease the minimum duty cycle of that
particular frequency.
Minimum % Duty Cycle versus Frequency for a PWM Output
Minimum
Duty Cycle (%)
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
3
1
0
PWM Frequency (Hz)
200
0
190
0
180
0
170
0
160
0
150
0
140
0
130
0
120
0
110
0
100
0
900 800 700 600 500 400 300 200 100 22
A PWM output is enabled by setting its output enable bit (in the module output data) to
ON. The output is disabled by setting its Output Enable bit to OFF.
Both frequency and duty cycle can be changed while the output is enabled.
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