5

Discrete Input Autotest

Discrete Input Autotest exercises the system inputs to assure their ability to detect and respond to actual inputs. It can be used on both 16-point and 32-point blocks.

Input autotest will:

Haccommodate normally-closed and normally-open devices with the device in either state.

Hdetect any input failure associated with an input that would result in a failure to respond.

Hnot cause spurious outputs.

Input autotest is internal to each Genius block. With the exception of an initiation command, it requires no interaction with the PLCs during the autotest sequence.

Configuration Required for Discrete Input Autotest

Blocks that will be autotested must be configured as ªcombinationº (input and output) blocks. However, the blocks must be used as all-input blocks with point 16 only on each block set up as an output. Point 16 must be configured to be ªDefault Onº.

Whether or not inputs on an input block group will be autotested is configurable on a circuit-by-circuitbasis.

Setup for Input Autotest

Inputs to be autotested must have their power controlled by circuit 16, which functions as the ªpower feed outputº.

Each power feed output is capable of providing power to up to 32 input devices.

Block Setup for Input Autotest

 

 

 

 

1

 

1

2

 

 

3

 

2

 

4

 

 

5

 

3

 

6

 

inputs

7

 

4

8

 

5

 

9

10

 

6

 

11

12

 

7

 

13

14

inputs

8

output

15

16

 

9

 

17

18

 

10

 

19

20

 

11

 

21

22

 

12

inputs

23

24

 

13

25

26

 

14

 

27

28

 

15

 

29

30

output

16

 

31

32

 

16-circuit block

32-circuit block

Installing isolation diodes permits the Input Autotest to also detect circuit-to-circuit shorts. When a single input sensor is wired to more than one input block, isolation diodes are also required on the power feed outputs.

The following illustration shows connections from a single input sensor to a group of three blocks. The Zener diode shown at the field switch is for line monitoring, as explained on page 5-14.

GFK-0787B

Chapter 5 Diagnostics

5-5

Page 65
Image 65
GE GFK-0787B user manual Configuration Required for Discrete Input Autotest, Setup for Input Autotest