Hardware reference guide

Intelligent/Special Purpose
35013379 11/2011 339
Rate Sample Mode Caution
If a version 02.00 or higher module replaces a module which has a version number
less than 02.00 in a Rate Sample mode application, extra software configuration
may be required.
Rate Sample mode is set using Command 1, CONFIGURE (01XX), 4X+1 register,
bit 13 = 1 (see the description of Command 1 in this section).
NOTE: To verify the version of the module, reference the indicated label found on
the top front of the module.
The following figure shows the module’s label.
In modules prior to V02.00, when Rate Sample mode was selected, input was
always handled as if it were generated by a pulse encoder. For example, 60 count
per revolution encoders, either pulse or quadrature types, would give a rate of 60 for
a one-second revolution when the interval was set for one second.
Users are cautioned that beginning with V2.00 modules, if a quadrature type
encoder is used to provide count input and Pulse/Quadrature Input Counter 1 and
2, bits 9 or 10, are set to 1, the module will detect all edges. The result is four times
the rate sample value as would be accumulated with an equivalent pulse encoder
input. In the example in the above paragraph, the rate sample would be equal to
240.
Encoder type selection is set using Command 1, CONFIGURE (01XX), 4X+1
register, bits 9 or 10 (see the description of Command 1 in this section).
If the Encoder Type select bits are set to 0, either type of encoder will produce the
Rate Sample, as did versions of the module that were lower than V02.00.