User manual

2. Rotate the SRV02 load gear, component #5 in Figure 2.1b, one rotation and the encoder should measure 4096
counts (or 8192 when using the SRV02-EHR option) in quadrature mode.
Note: Some data acquisition systems do not measure in quadrature and, in this case, one-quarter of the
expected counts are received, i.e. 1024 counts in the SRV02-E or 2048 in the SRV02-EHR. In addition, some
data acquisition systems measure in quadrature but increment the count by 0.25 (as opposed to having an
integer number of counts). Make sure the details of the data-acquisition system being used is known. The
counters on the Quanser DAQ boards measure in quadrature and therefore a total of four times the number
of encoder lines per rotation, e.g. a 1024-line encoder results in 4096 integer counts for every full rotation.
6.4.2 Troubleshooting
If the encoder is not measuring properly, go through this procedure:
• Check that the data-acquisition board is functional, e.g. ensure it is properly connected, that the fuse is not
burnt.
• Check that both the A and B channels from the encoder are properly generated and fed to the data-acquisition
device. Using an oscilloscope, there should be two square waves, signals A and B, with a phase shift of 90
degrees. If this is not observed then the encoder may be damaged and need to be replaced. Please see
Section 7 for information on contacting Quanser for technical support.
SRV02 User Manual 22