User manual

User Manual
man_905K_1.10.doc Page 43
4.7.2 Shaft Encoder Inputs
If the pulse inputs are connected to a shaft encoder (incremental or quadrature types), then the
Shaft Encoder Inputs option should be selected. The 905K will then look at both pulse input
signals and calculate a “position” value for the shaft encoder.
If an incremental encoder is used, then the correct counter value will be stored in the PI1
counter. If a quadrature encoder is used, the value will be stored in the PI2 counter. Note that
you don’t need to select which type of encoder is used. The 905K will calculate both values.
Only the base counters should be used; do not use the Hi or overflow counters.
If the pulse rate from the encoder is greater than 10Hz, then Fast Pulse Inputs should be selected
as for normal pulse inputs. The scaling divider for PI2 must be set to 1.
To physically set up the shaft encoder, set the shaft encoder to the middle of the range, then
manually set the counter value to the value required (refer section 5.3.2). As the encoder moves
up and down, the counter
value will increase or
decrease.
4.7.3 Pulse Rates
The 905K calculates the
rate of the pulse inputs
and makes these values
available to be mapped as
internal analog inputs.
For PI2, the pulse rate is
calculated on the scaled
counter - that is, after
the input is divided. The
maximum rate that can be
calculated for both inputs is
1000Hz.
The maximum value of the
pulse rate is user-
configurable. That is, you
select the maximum rate
that corresponds to 100% of
the analog value. For
example, if the normal
pulse rate is 35Hz, you may decide that the maximum signal should be 50Hz. The 905K will
then transmit 100% value at 50Hz. The maximum pulse rate can be configured from 0.02 Hz to
1000Hz.
For shaft encoder inputs, you can use PR1 for incremental encoders and PR2 for quadrature
encoders. The rate signal will be 50% for 0 Hz, between 50 – 100% when the encoder is
increasing and 0 – 50% when the encoder is decreasing. If you configure the maximum pulse