Precision in controlling actuators in relation to the target mechanical position is linked to three factors: the resolution of the , the speed and the reaction time of the module.
The resolution of the encoder
For a target precision of 0.1mm, the encoder should produce at least one or two pulses for 0.1mm.
NOTE:
Depending on the selected, the resolution must be taken into account:
For the required position, and depending on the approach speed, the system should have a maximum reaction time.
Example: reaction time required for a target precision of 1mm.
Using the module in an application is justified for speeds between 10 and 300m/min.
For a movement speed of<10 m/min, the entire application could be handled by a TSX PLC.
The minimum reaction time of the CCY 1128 module is 0.2ms, the maximum movement speed is therefore 300m/min.
Structural diagram of cam processing
The TSX CCY 1128 cam module optimizes its reaction time for controlling outputs depending on the parameters configured for the application.
The duration of the acquisition loop corresponds to the cycle for reading the absolute encoder via its SSI link. It is always synchronous with the calculation loop. The reading period is configurable (50 micro seconds, 100 micro seconds, 200 micro seconds).
The value selected must be dependent on the length of the SSI frame (number of bits), and the distance (l) between the encoder and the module.
The output refresh period is fixed by the calculation loop:
With the incremental encoder, it is automatically fixed by the module depending on the number of cams used by the (50 micro seconds up to 16 cams, 100 micro seconds up to 32 cams, 200 micro seconds up to 128 cams).
For an SSI encoder, the calculation period is optimized according to the number of cams configured, but cannot be less than the reading period.
For example: if T1 = 100 micro seconds then T2 = 100 micro seconds for a configuration of between 1 and 32 cams, T2 = 200 micro seconds for a configuration of between 33 and 128 cams.
This is used to compensate for the fixed delay introduced by the actuator and its associated mechanics. The calculation loop ensures that the anticipation value for switching each output is updated.
