6602

[Vivian]

I am using PCI-6602  as incremental encoder for an encoder measurement application. My encoder's output is up/down signal (two pulse signal). I have made the connections: CH1_A *(encoder) to SOURCE_0 and CH1_B*(encoder) to UP_DOWN_0. The encoder is seem working properly, and no errors. However, I confused about the settings of PCI-6602 in Simulink.

Since my output is UP/DOWN signal, so I chose the 'Two-Pulse Signal' in PCI-6602, and set the Index Phase to 'A high B low'. But when I run it to collect the data position, I could not gain the exact answer as I expeted. The value of position always is the half of the exact position value. I am wondering why is this happened, and what is the CORRECT settings for the PCI-6602.

I am very appreciated if any input you may have about this !!!

Thanks !

-vivian

[Kevin_Price]

Only a couple generic little thoughts.

Have you tried ignoring the Z-index?  Are you still off by a factor of 2?  I know that using Z-indexing successfully with a two-pulse encoder tends to be tricky to get right.  It may even be impossible to get completely consistent behavior in both directions, depending on exactly how the manufacturer chose to sync the Z-index to the Up and Down pulses.

Are you certain you've got your scaling set up properly, with the right value for "pulses per rev?"  One way to troubleshoot: 

Set up scaling with units="ticks."  When you read the count value, read it as a U32 (an unsigned 32-bit integer).  See whether the # of actual counts seems to be right.  If so, then perhaps you've got a scaling problem.

Don't know anything at all about how to interact with a 6602 from Simulink.  Is it possible that the interface to the board through Simulink only gives you a subset of the board's inherent functionality?

-Kevin P.

[Vivian]

Dear Kevin,

yeah ! I was instructed by my Prof to use the PCI6602 with the xPC (Matlab) in controlling the machine. However, until today; I still cannot get any acceptable results from this connections!

In my project, I used ZYGO-ZMI 501 Laser Measurement System: ZMI 501 Displacement Measuring Interferometer System. I have set the output from the encoder as Quadrature output signal. Since this encoder is negative trigger signal, so I connect the Ch1_A* to SOURCE_0 (pin-2) and Ch1_B* to UP_DOWN_0 (pin-40) at PCI-6602; and same for the remaining four channels. Then I set 'Quafrature Mode X4' in the counting mode at the PCI-6602 block in Simulink-XPC.

The signal which I collected from the encoder seem nothing and useless when comparing  to my previous work on another card on the same machine.

I am stucked and totally blank currently. No way for me to continue any more.

I really hope can hear some advices and suggestions from those experts who have read my message!

Thanks a lot!

-vivian

[josef_slg]

Hey,I am also busy with getting encoder readings right with the pci6602. try to connect phase B to pin 48(PFI6) and encoder 2 pahse b to pfi7 (pin15). II still have some problems with synchornizing, getting the clock source right and triggering. But can wirte readings to .csv file. You might help me and tell me how to do.  Or  you might sent mi the vi.
Thanks in advance.