ElmoMC SimplIQ Software Manual - Manual (Page 117)

SimplIQ Software Manual Commutation
MAN-SIMSW (Ver. 1.4)
8-7
8.3.4.3 Encoder Parameterization
Accurate commutation requires a high-resolution sensor. Many types of high-resolution
sensors exist. For the
SimplIQ drive, the following selections are available:
Parameter Description
CA[17]
Commutation sensor type: 1 for Main encoder.
CA[21] Position sensor present:
0: No high-resolution commutation sensor. Commutation will be based on
digital Hall sensors only.
1: Main position sensor will be used for commutation.
The encoder is normally used both for motion feedback and for commutation. As a motion
feedback counter, it must count up when the motor goes forward, in the application sense.
As a commutation counter, it must count up when the commutation angle increases. These
two requirements are not necessarily the same, so the following two parameters are needed:
Parameter Description
CA[16]
Encoder direction: Set 0 or 1 so that the encoder will count forward in the
desired movement direction.
CA[25] Motor direction: Set 0 or 1 so that with positive torque, the motor will
rotate in the direction for which the encoder counts up.
The encoder measures the shaft angle. In order to commutate, the encoder count per
electrical revolution is needed. Normally, the number of encoder counts per motor
revolution is an integer (if not, commutation with an encoder may be incorrect). The number
of pole pairs per revolution is always an integer. By knowing the encoder counts per
mechanical revolution, along with how many pole pairs are in a revolution, the
commutation counter can infinitely update without accumulate errors.
For linear motors, the number of pole pairs CA[19] should be set to the largest number of
full electrical cycles possible for that motor. Enter the “encoder counts in revolution” CA[18]
parameter as the number of encoder counts for CA[19] electrical cycles.
The following table lists the encoder parameters:
Parameter Description
CA[18]
Encoder bits per revolution, after resolution multiplication by 4, in the
range [6…2
24 =16,777,216]. For an incremental encoder with 1000 lines,
CA[18] will be 4000.
CA[19] Number of motor pole pairs: [1…50].
CA[23] Counts per meter (an positive integer):
0: Rotary motor
1: Counts per meter in linear motor
This parameter is not used directly by the drive; it is just stored there for
the convenience of the host.
Table 8-3: Encoder Parameters