Choice of encoders for the TSX CCY 1128

Introduction

The TSX CCY 1128 module inputs are able to receive signals from the following encoders:

incremental,
absolute with SSI serial outputs,
absolute with parallel outputs. This last type requires the use of a specific interface TELEFAST ABE-7CPA11.

The user can choose from these encoder types according to the requirements.

Encoder output interface

The table below summarizes the main characteristics of the output interface for the encoder types normally used.

Type of encoder	Supply voltage	Output voltage	Types of interface
Incremental	5 VDC	5 VDC differential	Outputs with line transmitters to RS 422 standard, with 2 outputs per signal A+/A-, B+/B-, Z+/Z-
Incremental	10...30 VDC	10...30 VDC	Totem Pole outputs with one output per signal A, B, Z
Absolute with SSI outputs	10...30 VDC	5 VDC differential	Output with line transmitters to RS 422 standard for the data signal (Data SSI) RS 422 compatible input for the clock signal (CLK SSI).
Absolute with parallel outputs	5 VDC or 10...30 VDC	5 VDC or 10...30 VDC	Parallel outputs. Require the use of the Telefast ABE-7CPA11 interface to transform parallel output signals into serial signals.

Encoder supply

The design of the module allows an encoder supply of:

5 VDC
24 VDC, standardized voltage in the 10…30 VDC format.

The choice of supply voltage is dependent on the encoder supply voltage.

5 VDC encoder supply

For encoders with a 5 VDC supply, voltage falls must be taken into account. These are dependent upon:

the length of the cable between the module and the encoder (double length),
the section of wire,
the encoder consumption.

The acceptable voltage fall for the encoder is generally 10% of the nominal voltage.

The table below gives the on-line voltage fall, according to the section of the wire, for a 100 meter length of wire with a given encoder consumption.

Section of wire	Voltage fall for a 100 meter length of wire with an encoder consumption of:
Section of wire	50 mA	100 mA	150 mA	200 mA
0.22 mm = gauge 24	0.4 V	-	-	-
0.34 mm = gauge 22	0.25 V	0.5 V	-	-
0.5 mm	0.17 V	0.34 V	0.51 V	-
1 mm	0.09 V	0.17 V	0.24 V	0.34 V

CAUTION

POTENTIAL MODULE DAMAGE

Do not raise the supply voltage of the encoder to compensate for an online voltage fall. After a break in the supply, there is a risk of an overvoltage at the module inputs.

Failure to follow these instructions can result in injury or equipment damage.

24 VDC encoder supply

Encoders with a supply voltage of 24 VDC are recommended for the following reasons:

the supply source does not need to be completely accurate. As a general rule, these encoders use a supply format of 10…30 V.
an on-line voltage fall is of little significance due to a substantial distance between the module and the encoder.

Ground connection continuity

In order to ensure correct operation during interference, it is vital:

to choose an encoder with a metal casing that is referenced to the protective ground of the connected device.
that the ground connection is continuous between:
- the encoder,
- the shielding of the connector cable,
- the module.