Configuring an incremental encoder

Role

an allows you to:

declare that the inputs are connected to an incremental encoder,
define the processing characteristics of the encoder signals.

Procedure

The table below describes the procedure:

Step	Action
1	Select Incremental encoder in the input Interface field in the Acquisition configuration screen.
2	Click on Configuration to display the following dialogue box :
3	Select the counter input filtering according to the maximum frequency supplied by the encoder : 125 kHz x1 / 125 kHz x4 enables good running for frequencies lower than 125 kHz in input (with or without multiplication by 4), 500 kHz x1 / 250 kHz x4 corresponds to the module's limit values.
4	If necessary check the function Reading inversion. This parameter defines the direction in which the measurement changes in relation to the direction of rotation of the encoder.
5	Enable if necessary the function Line check. This function indicates any electrical faults (line break or short-circuit) on the links with the RS422 encoder. This function must not be used with an encoder with 10...30V totem pole outputs.
6	Select multiplication by 1 or by 4. Multiplication by 4 gives a resolution 4 times greater than the resolution of the encoder.
7	Click on OK to confirm the choices made.

Configuration

The configuration gathers together the data which characterizes the machine (invariant) and which is necessary for the TSX CCY 1128 module to operate.

All this information is stored in the PLC %KW constants zone. The PLC application cannot modify them.

Filtering

Filtering allows better environmental handling (for difficult environments). It is a filter that limits the bandwidth of counting signals which come from an incremental encoder.

With filtering the permitted frequency (before multiplying by 4) is 125 KHz, as against 250 KHz without filtering.