some questions about electronic gearing

[bgrain]

hi everyone
i am a little confused with the electronic gearing.It says that the master can be another axis or an encoder or ADC.I want to kown if  the encoder or ADC here can be any one of the four(i am using pci7344).If the the slave the axis is set to be servo mode,can it use its feedback device as the master device?
anoter question ,i kown that under gearing mode it can response fast,then does the pid update period work?if the slave axis is a servo axis dose it works in the normal mode that is completing a controll loop in one pid update period?
suppose such a case that  a ADC channel  is used as master and it transforms the analog  voltage to the digital as fast as it can but the pid update period is set to be 0.5ms for example.then what happens?

[Jochen]

The slave axis can use any encoder and ADC as master resource but it's own feedback source.
In gearing mode the trajectory data is not generated by the onboard controller of the board but the dynamic setpoints for the PID are directly retrieved from the master resource. For the case that you are using an ADC as master device the ADC is sampled at the rate of the PID loop of the slave axis.
Please note that for the PCI-7344 there is only a resolution of 12 bit for the ADCs. Thus the resolution is limited to -4097 to +4098 steps which might be very rough.

I hope that helps.

Best regards,

Jochen Klier
National Instruments Germany

Message Edited by Jochen on 08-08-2005 05:06 PM