Input range selection – Rockwell Automation 1771-IFE , D17716.5.90 USER MNL. ANALOG INPUT Module User Manual

Page 31

Module Configuration

Chapter 4

4-2

You can configure the module to operate with any of five voltage or three
current ranges. You can select individual channel ranges using the
designated words of the write block transfer instruction (Table 4.A). Use
BTW word 1 for range selection of channels 1 through 8, and BTW word 2
for channels 9 through 16. Two bits are allocated for each channel. For
example, for channel 1, set word 1 bits 00-01 as shown in Table 4.A.

Table 4.A

Input Range Selection Bits

Bit 01

Bit 00

Voltage or current input

1 to 5 V DC, 4 to 20 mA

0 to 5 V DC, 0 to 20 mA

Ć5 to +5 V DC, Ć20 to +20 mA

1,2

Ć10 to +10 V DC

, 0 to 10 V DC

Current input mode selected by configuration plug.

Configurable using biĆpolar scaling.

Table 4.B shows the incremented voltage or current assigned to each bit for
the seven different input ranges. For example, if the channel 1 input range
is 0 to +5V and the actual incoming signal is at mid-range (+2.5V) the
value in the module’s data word would be 0000 1000 0000 0000 (binary)
or 2048 (decimal). The input is 2048/4096, or 1/2 of full scale.

Table 4.B

Input Voltage and Current Ranges for the Analog Input Module

Nominal Voltage or

Current Range

Corresponding 4ĆDigit

BCD Output Range

Corresponding 12ĆBit

Binary Output Range

Voltage or

Current Per Bit

+1 to +5V

0000 to +4095

0000 to + 4095

0.98mV

0 to 5V

0000 to +4095

1.22 mV

Ć5 to +5V

Ć4095 to +4095

1.22mV

Ć10 to +10V

Ć4095 to +4095

2.44mV

0 to +20mA

0000 to +4095

.0049mA

+4 to +20mA

0000 to +4095

.0039mA

Ć20 to +20mA

Ć4095 to +4095

.0049 mA

Note:

Voltage and current input ranges are selectable on a per channel basis.

Input Range Selection