GE VersaMax IC200PWR001 User Manual page 457

13
IC200MDD841
Mixed Module, 24 V DC Positive Logic Input 20 Points / Output 12 Point /
(4) High-speed Counter, PWM, or Pulse Train Configurable Points
Pulse Train Outputs
Pulse Train outputs can be used to control stepper motors. Use of an output for
this function is set up as part of the module configuration. When configured as
Pulse Train outputs, the pulse frequency is specified in the module's output
data, as described later in this section. (Refer to Module Data.) The range is
11Hz to 5 kHz. The module's output data is also used to set the number of
pulses to be emitted.
The Pulse Train starts when its Output Enable bit is ON and its Pulse Train
Start bit transitions from Off to ON. When the Pulse Train starts, its Pulse Train
Complete status bit is set OFF. When the Pulse Train is complete, the module
sets a status bit that can be read by the CPU or computer.
Note: Once a Pulse Train is started, it continues until it has completed or until
its Output Enable (%Q) bit goes to 0.
Optical Isolator Correction Factor
The performance of the optical isolators used in the module varies as the
temperature changes. This affects the accuracy of the duty cycle for both PWM
and Pulse Train outputs. To compensate for this, the module incorporates a
user configurable Optical Isolator Correction Factor. The default Correction
Factor is 75µS in duration. The Correction Factor can be changed within the
range 0 to 200µS by sending the new value in the module's output data. An
example is illustrated below. In the diagram, T0 is the OFF Time, which is
1
, where f is the pulse frequency.
+
Correction
2 f
1
1 =
, T2 = Optical Isolator Delay, and T1+T2 = ON Time.
T
2 f
Output
Voltage
T0 T1 T2 T0 T1 T2
Time
GFK-1504N Chapter 13 Mixed Discrete/High-Speed Counter Module 13-17