Rockwell-automation 1771-QB Linear Pos. Manual de usuario descargar pdf (Pagina 37)

Hardware Description

Chapter 4

48

The analog output interface circuit is electrically isolated from the 1771 I/O

chassis. This feature protects other devices on the 1771 backplane from noise

and current surges in the analog output circuit. An internal relay automatically

shuts off these outputs in the event of a module fault. For details on connecting

the servo valve interface, see Chapter 5.

Important: Throughout this manual we refer to servo valves, but you can also

use the analog outputs to control proportional valves. All references to servo

valves also apply to proportional valves.

Terminals 36 through 39 on the module’s wiring arm provide connection points

for discrete output signals. Each axis has two discrete outputs: Output 1 which

can be configured to be either an in-position or programmable output, and

Output 2 which can be configured to be either a loop fault or programmable

output. (See Chapter 9.) The default configuration is in-position and loop fault.

The discrete outputs are current sources. Figure 4.4 gives a simplified schematic

of a discrete output circuit.

Figure 4.4

Simplified

Schematic of a Discrete Output

50042

1771  QB MODULE

OUTPUT SUPPLY

3.9

OUTPUT 1

Here are the characteristics of the discrete outputs:

Low no voltage applied to the output

High output supply voltage applied to output

Maximum Current 100 mA

Voltage Drop 1.6 VDC maximum (at 100 mA) between the

discrete output power supply (terminal 40) and the

discrete outputs

Discrete Outputs

1 2 ... 32 33 34 35 36 37 38 39 40 41 42 ... 225 226

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Rockwell-automation 1771-QB Linear Pos. Manual de usuario Pagina 37