Rockwell-automation 1771-QB Linear Pos. Manual de usuario descargar pdf (Pagina 86)

Formatting Module Data (WRITES)

Chapter 7

77

Figure 7.4

Analog

Calibration Constant W

ords

50027

Analog calibration constant for positive motion,

BCD 99.99 ips or 999.9 mmps max

Binary 327.67 ips or 3276.7 mmps max

Analog calibration constant for negative motion,

BCD 99.99 ips or 999.9 mmps max

Binary 327.67 ips or 3276.7 mmps max

Note: ips = inches per second

mmps = millimeters per second

15 14 13 12 11 10 09 08 07 06 05 04 03 02 01 00

For servo valves, the analog calibration constants can be roughly calculated

from the diameter of the cylinder and the maximum flow rate of the valve. You

will fine-tune these parameters when you perform the tuning procedure given in

Chapter 8.

Transducer Calibration Constant (words 5, 6 and 34, 35)

The module uses the transducer calibration constant to convert the transducer

generated pulse width into an axis position reading.

Calculate the transducer calibration constant by multiplying the figure stamped

on the side of the transducer head by the number of circulations that you are

using. This figure varies slightly from one transducer to another. It is typically

9.0500 microseconds per inch or 0.35600 microseconds per millimeter.

Example: If your transducer is stamped with 9.0500 microseconds per inch

and you’ve programmed your digital interface box for four circulations, your

transducer calibration constant would be:

4 x 9.0500 = 36.2000

See Chapter 4 to determine the optimum number of circulations for your system

and Chapter 8 for a procedure for verifying the transducer calibration constant.

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Rockwell-automation 1771-QB Linear Pos. Manual de usuario Pagina 86