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Proportional outputs
7 I/O functionality
Instruction book, IQAN-MC3
Connecting loads to proportional outputs
The current outputs are high performance outputs with closed loop current control
designed to drive proportional electrohydraulic valves. For COUT and load
characteristics, please see Appendix A.
Connecting a load, e.g. one proportional valve section, to the current mode or PWM
mode outputs is done by using the COUT/CRET paired positions.
When a COUT is used with a just single solenoid connected (e.g. a hydraulic motor),
the application file must be configured so that the COUT is not bidirectional; otherwise
an open load will be detected.
NOTICE
DO NOT install diodes across coils!
Proportional outputs in PWM mode
It is possible to configure the proportional outputs for PWM mode, and control the
output directly with the modulation ratio instead of closed loop current control. In
PWM mode, the current is not measured, and diagnostics are limited.
NOTICE
The PWM outputs on an IQAN-MC3 can not be used to drive Pulsar valves, select
another IQAN module to do that.
COUT mode output diagnostics
The COUT is capable of detecting internal faults as well as wiring faults. The fault will
be identified as one of the following status values in IQANdesign.
• Over load (e.g. over current)
• Open load (e.g. open circuit or under current)
• "Error - internal error in the IQAN-MC3 power driver
The reported status is describing the most likely fault condition, but in certain cases the
status will not match the actual fault. For details on failure modes, see Appendix B, on
page 51.
EXAMPLE
Positive direction:
Connect the proportional valve to the COUT and the CRET+, respectively.
Negative direction:
Connect the proportional valve to the COUT and the CRET-, respectively.
Connecting a load to a proportional output.
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