144
ifm
Programming Manual
ecomatmobile
CabinetController (CR0301) Runtime System V05
2016-04-21
ifm function elements
ifm function elements for the device CR0301
>
PWM dither
1534
For certain hydraulic valve types a so-called dither frequency must additionally be superimposed on
the PWM frequency. If valves were triggered over a longer period by a constant PWM value, they
could block due to the high system temperatures.
To prevent this, the PWM value is increased or reduced on the basis of the dither frequency by a
defined value (DITHER_VALUE). As a consequence a vibration with the dither frequency and the
amplitude DITHER_VALUE is superimposed on the constant PWM value. The dither frequency is
indicated as the ratio (divider, DITHER_DIVIDER • 2) of the PWM frequency.
>
Ramp function
1535
In order to prevent abrupt changes from one PWM value to the next, e.g. from 15 % ON to 70 % ON, it
is possible to delay the increase by using
PT1
(
). The ramp function used for PWM is
based on the CODESYS library
UTIL.LIB
. This allows a smooth start e.g. for hydraulic systems.
964
NOTE
When installing the
ecomatmobile
DVD "Software, tools and documentation", projects with examples
have been stored in the program directory of your PC:
…\ifm electronic\CoDeSys V…\Projects\DEMO_PLC_DVD_V…
(for controllers) or
…\ifm electronic\CoDeSys V…\Projects\DEMO_PDM_DVD_V…
(for PDMs).
There you also find projects with examples regarding this subject. It is strongly recommended to follow
the shown procedure.
The PWM function of the controller is a hardware function provided by the processor. The PWM
function remains set until a hardware reset (power off and on) has been carried out on the controller.
Summary of Contents for Ecomat 100 Mobile CR0301
Page 212: ......
