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Diagnostic digital outputs
Instruction book, IQAN
Diagnostic digital outputs
The IQAN-MC31 has two types of digital outputs. When used in pairs, high-side +
low-side, diagnostics may be performed. DOUT A-E are the designations for the paired
DOUT channels. DOUT-A = DOUT-F (HS) + DOUT-K (LS) and so on. For current
ratings on the DOUT’s, see Appendix A.
Connecting loads to diagnostic digital outputs
Connecting of loads to the digital outputs such as on/off valves is done by using the
DOUT (HS)/DOUT (LS) paired positions.
Protection against voltage transients
A clamping diode must be placed between the digital output (HS) and digital output
(LS), as close to the load as possible. This reduces EMI, it also helps in protecting the
output against high voltage transients. Use the diode:1N5408 (3A/1000V).
Depending on the load, other clamping diodes might be used instead.
DOUT output diagnostics
The diagnostic DOUT 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-MC31 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.
There are faults that are detected on startup, and that will prevent the module from
starting the application. These are all faults where an output is connected to +BAT on
startup.
To detect these faults, it is important that all connectors are plugged-in before the
module is started. See section Start-up, also see Appendix B.
EXAMPLE
Connect the on/off valve to the digital output using the DOUT (HS) and the DOUT
(LS) as return, respectively.
Connecting a load to the diagnostic digital output.
d1
IQAN-MC31
DOUT (LS)
DOUT (HS)
