Encoder Type
(Original Document)
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At a Glance
The Input interface field allows you to choose the encoder type: incremental encoder or absolute SSI encoder.
To access the input interface parameters screen, press the Configuration button: Input interface details.
Incremental Encoder Parameters Screen
In the event of an incremental encoder, the configuration screen of the input interface is as follows:
Incremental Encoder Parameters
The parameters of an incremental encoder are as follows:
Parameter
Description
Measurement inversion
If you check this box, the direction in which the measurement changes will be reversed.
Multiplication by 1 or multiplication by 4
Multiplying by 4 increases the precision of the encoder:
  • for any given encoder, the precision will be 4 times greater,
  • to obtain a given resolution, you can use a resolution encoder, which is 4 times smaller.
The following diagram illustrates multiplication by 4
RE, corresponding to the resolution obtained by multiplication by 4, is also called equivalent resolution.
Absolute Encoder Parameters Screen
The input interface configuration screen is used to define the characteristics of the SSI frame used by the encoder.
Encoder Field Description
The Encoder field is used to define the type of coding:
Parameter
Description
Direct offset or assisted offset
With a direct offset, you must specify the offset value in encoder points. With assisted offset, the offset is calculated by the module, using a position value supplied by the user. By default, direct offset is selected.
Binary or Gray
These selection buttons are used to define the code used by the encoder: binary code or Gray code (binary code by default).
Measurement inversion
This parameter defines the measurement inversion; in other words it defines direction in which the measurement changes for a given encoder rotation direction. This parameter is inaccessible from an infinite machine.
Description of SSI Frame Field
The SSI frame field is used define the characteristics of the frame:
Parameter
Description
No. of header bits
Number of frame header bits (not significant): 0 to 4 (0 by default).
No. of encoder data bits
Number of frame data bits for the modules:
TSX CAY 21/41:16 to 25 (16 by default),
TSX CAY •2/33:12 to 25 (12 by default).
No. of status bits
Number of frame status bits: 0 to 3 (0 by default). If you choose a number of bits other than 0 it will give access to the error bit and its position (Position 1 to 3) in the status bits zone.
Presence of parity bit
Presence or absence of parity bit (absence by default). If this box is checked, you can define the type of parity: even or odd.
If you select odd parity, the module will no longer perform the parity check and the parity bit will be managed as a status bit.
Frame
Redisplays the characteristics defined for the SSI frame.
Addresses:
1 : number of header bits
2 : number of data bits
3 : number of status bits
4 : presence of parity bit P: parity, I: Odd
Absolute Encoder with Parallel Outputs
It is possible to connect an absolute encoder with parallel outputs, using an ABE-7CPA11 conversion interface. In this case, you must enter the configuration of an absolute SSI encoder.