Installation Manual Installation Manual

Add to my manuals
154 Pages

advertisement

Installation Manual Installation Manual | Manualzz

3

Input / Output

3

3.1

Outline

This section describes the various digital and analog input and output capabilities of the MintDrive, together with descriptions of each of the associated connectors on the front panel.

The following conventions will be used to refer to the inputs and outputs:

I/O

DIN

. . . . . . . . . . .

. . . . . . . . . .

DOUT

AIN

. . . . . . . .

. . . . . . . . . .

AOUT . . . . . . . .

Input / Output

Digital Input

Digital Output

Analog Input

Analog Output

3.2

Analog I/O

The MintDrive provides:

H

4 analog inputs, 2 on the block connector X11 and 2 on the 25-pin D-type connector X5

H

4 analog outputs, 2 on the block connector X11 and 2 on the 25-pin D-type connector X5.

None of the analog I/O are optically isolated from internal generated power rails, therefore care must be taken to avoid earth loops and similar associated problems.

The input buffers do not offer any low pass filtering of the applied voltage. Any system noise presented at the input will be reflected in the value read on conversion. Therefore, each analog input signal should be connected to the system using individual screened/shielded cable (a twisted pair cable in the case of the differential inputs) with an overall shield in order to minimize these effects. The overall cable shield should then be connected to the chassis at one end. No other connection should be made to the cable shield. If any inputs are unused, then it is advisable to connect them to the AGND pin. Do not leave the inputs unconnected (floating).

27

3.2.1

Analog Input, Single Ended - X11

1

2

Location

Connector X11, pins 1 & 2

Name

AIN2

Mint keyword

ADC.2

Description

Single ended input.

Range: 0 - ±10VDC.

Resolution: 9-bit with sign.

Input impedance: >4k Ω .

Sampling interval: 5ms.

Note:

There is a +15V reference voltage supplied on X11 pin 3 from a 1.96k

Ω resistor.

A linear command potentiometer of 5k Ω may be used, with X11 pin 2 connected to the wiper, and the end terminations connected to pins 1 & 3, as shown below.

5k potentiometer

or

Ω , 0.25W

0-10VDC

X11

GND

1

Input

Reference

2

3

AIN2

(

ADC.2

)

Figure 10 - AIN2 analog input wiring

28

3.2.2

Analog Input, Differential - X11

4

5

Location

Connector X11, pins 4 (+) & 5 (-)

Name

AIN3

Mint keyword

ADC.3

Description

Differential input.

Common mode voltage range: ±10VDC.

Resolution: auto-selecting as follows:

12-bit with sign (<1V DC input)

9-bit with sign (>1V DC input)

Common mode rejection: 40dB

Input impedance: >5k Ω

Sampling interval: 5ms

Optional 4-20mA current mode (contact Baldor).

A typical input circuit is shown below:

X11

+24VDC

1.5k

Ω , 0.25W

0V

1k Ω , 0.25W

potentiometer

Input+

4

Input-

5

Figure 11 - AIN3 analog input

AIN3

(

ADC.3

)

29

3.2.3

Analog Inputs, Differential - X5

1

14

Location

Connector X5

Pins

Name

8 (+) and 21 (-)

AIN0

9 (+) and 22 (-)

AIN1

Mint keyword

ADC.0

ADC.1

Description

Two independent differential inputs.

Common mode voltage range: ±10VDC.

Resolution: 12-bit with sign.

Common mode rejection: 40dB

Input impedance: >22k Ω

Sampling interval: 0.5ms - 20ms (depends upon servo loop frequency).

Accuracy: better than 1%

13

25

Typical use for these may be analog sensor inputs or to provide a low cost joy-stick interface.

The guaranteed DC accuracy of the inputs is 2%. Each input is buffered individually, before being fed into separate channels of the ADC, a Maxim MAX197. There is some input protection should the input voltage exceed the maximum rating shown above, although this is for protection against transitional over-voltage; long term over-voltages will cause permanent damage.

Each analog input signal should be connected to the system using a screened/shielded twisted pair cable, and the cable shield should be connected to the chassis at one end. Due to the differential characteristics of these inputs, they can provide better rejection of common mode noise provided normal good engineering practices are adhered to. No other connection should be made to the cable shield.

X5 X5

Input +

8

Input -

21

GND

20

AIN0

(

ADC.0

)

Input +

9

Input -

22

GND

20

AIN1

(

ADC.1

)

Figure 12 - AIN0 and AIN1 analog inputs

30

If an input is unused, then it is advisable to connect it to the AGND pin. Do not leave the input unconnected (floating).

The analog inputs can be read in Mint using the keywords

ADC.0

and

ADC.1

. Mint will return the value as a percentage where 0V=0%, -10V= -100% and +10V = 100%.

CAUTION

: The isolation provided on the inputs, outputs, master encoder and CAN is nominal. The primary function of the isolation is to break earth loops. Both sides of the isolation boundary must still be kept at SELV potentials with respect to ground, i.e. the difference in the 0V rail across the isolation boundary must not exceed 30V.

31

3.2.4

Analog Outputs, Bipolar - X11

6

7

Location

Connector X11

Pins

Name

6

AOUT2

7

AOUT3

Mint keyword

AUXDAC.2

AUXDAC.3

Description

Two independent assignable outputs.

Output range: ±10VDC.

Resolution: 8-bit with sign.

Output current: 1mA maximum.

Update interval: 2ms.

Two programmable analog outputs that can be used to provide real time status of various control conditions. The voltage from the output buffer is supplied through a 50 Ω resistor for short circuit protection.

GND

X11

1

Output 2

Output 3

6

7

AOUT2

(

AUXDAC.2

)

AOUT3

(

AUXDAC.3

)

Figure 13 - AOUT2 and AOUT3 analog outputs

CAUTION

: Following power-up or a system reset, both outputs will initially be set at approximately +10V. This condition will remain, for a short period, during the software initialization process. For this reason, care should be taken if this output is being used as a drive reference for a speed controller.

32

3.2.5

Analog Outputs, Bipolar - X5

Location

Connector X5

Pins

Name

19

AOUT0

7

AOUT1

Mint keyword

AUXDAC.0

AUXDAC.1

Description

Two independently controlled outputs.

Output range: ±10VDC.

Resolution: 8-bit

Output current: ±4mA maximum

Update interval: immediate, using Mint commands

1

14

13

25

The two analog 8-bit outputs AOUT0 and AOUT1 are not isolated and are primarily intended for system debugging. Output voltages in the range of ±10V are achievable with a DC accuracy of better than 3%.

They are derived from a high-frequency PWM pulse train from the main processor, which is subsequently filtered. These signals are buffered by an operational amplifier in the MintDrive and are capable of sinking or sourcing up to ±4mA. The outputs are protected by fast Schottky diodes against excessively high transitional voltages of either polarity.

X5

Output 0

19

AOUT0

(

AUXDAC.0

)

Output 1

7

AOUT1

(

AUXDAC.1

)

GND

20

Figure 14 - AOUT0 and AOUT1 analog outputs

CAUTION

: Following power-up or a system reset, both outputs will initially be set at approximately +10V. This condition will remain, for a short period of time during the software initialization process.

33

advertisement

Was this manual useful for you? Yes No
Thank you for your participation!

* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project

Related manuals