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Hardware first notch filter – Rockwell Automation 1794-IT8,D17946.5.7 Thermocouple/Millivolt Input Module User Manual

Page 29

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4–3

Writing Configuration to and Reading Status from your Module with a Remote I/O Adapter

Publication 1794-6.5.7 – April 1997

You select input scaling using the designated words of the write
block transfer instruction. Refer to the Bit/Word description for write
word 0, bits 00 and 01.

A hardware filter in the analog to digital converter lets you select a
frequency for the first notch of the filter. Selection of the filter
influences the analog to digital output data rate and changes the
module throughput. Module throughput is a function of the number
of inputs used and the first notch filter. Both of these influence the
time from a thermocouple input to arrival at the backplane.

Throughput in Normal Mode

A/D Filter First Notch

Frequency

(effective resolution)

10Hz

(16-bits)

25Hz

(16-bits)

50Hz

(16-bits)

60Hz

(16-bits)

100Hz

(16-bits)

250Hz

(13-bits)

500Hz

(11-bits)

1000Hz

(9-bits)

Number of channels

scanned

System Throughput (in ms and s)

1

325

145

85

75

55

37

31

28

2

650

290

170

150

110

74

62

56

3

975

435

255

225

165

111

93

84

4

1.3s

580

340

300

220

148

124

112

5

1.625s

725

425

375

275

185

155

140

6

1.95s

870

510

450

330

222

186

168

7

2.275s

1.015s

595

525

385

259

217

196

8

2.60s

1

1.16s

680

600

440

296

248

224

1

Default setting

Hardware First Notch Filter