Calibrating your input module, Offset calibration – Rockwell Automation 1771-IFF/A,D17716.5.116 FAST ANALOG INPUT MODULE User Manual

Page 13

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Calibrating Your Module

Publication 1771Ć6.5.116 - July 1996

The fast analog input module is shipped already calibrated.
Calibration of the module consists of applying a voltage or current
across each input channel for offset and gain calibration. Offset and
gain values are shown in the following table.

Table1.A

Offset and Gain Values for Calibrating the 1771ĆIFF/A Fast

Analog Input Module

SingleĆended

Differential

Range

Offset Value

Gain Value

Offset Value

Gain Value

1 to 5V

0V

5.000V

0V

5.000V

0 to 5V

0V

5.000V

0V

5.000V

-5 to +5V

0V

5.000V

0V

5.000V

-10 to +10V

0V

10.000V

0V

10.000V

0 to 10V

0.V

10.000V

0V

10.000V

4 to 20mA

0.000mA

20.000mA

0.000mA

20.000mA

0 to 20mA

0.000mA

20.000mA

0.000mA

20.000mA

-20 to +20mA

0.000mA

20.000mA

0.000mA

20.000mA

Offset Calibration

Normally all inputs are calibrated together. To calibrate the offset of
an input, proceed as follows:

1. Apply power to the module.

2. Apply the offset voltage of 0V or current of 0.000mA (Table 1.A)

as required to all 16 channels (8 in differential mode).

3. After the connections stabilize, set all bits in write word 38 to 1

and all bits in word 39 to 0. Send a 39 word block transfer write
(BTW) to the module to calibrate the offset. Refer to chapter 4.(In
Differential mode, the upper byte of word 38 is not set (bits 8–15
decimal or 10–17 octal are 0).)

When the BTW is sent, all channels are calibrated to 0.000V.

Write Block Transfer Word 38 for Offset Calibration

Decimal Bits

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

Octal Bits

17 16 15 14 13 12 11 10 07 06 05 04 03 02 01 00

Channel

16 15 14 13 12 11 10

9

8

7

6

5

4

3

2

1

Word 38

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

Chapter 4

Calibrating your Input

Module

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