FC 42 - Digital Input / Loop

The digital input/loop function code acquires digital signals via the communication highway in the same loop. The input points are located in other Harmony control units (HCUs) and must have an exception report defined (e.g., digital exception report, function code 45). Updates are on an exception report basis. Exception report intervals are specified in the executive block or the segment control block. Use function code 122 for communication to other loops.

 

To insure that the module successfully acquires a signal from another node, the digital signal generates a point quality flag. To test the quality of the signal, include a function code 31 in the configuration. The quality of the point cannot be determined by any other type of block. The output of the test quality block can be used as an input to other digital processing blocks to provide signal quality information.  Refer to Appendix H, for a definition of point quality.  Use function code 69 to test the alarm associated with the analog input/loop function block.

 

 

 

Outputs:

Blk

Type

Description

N

B

Value of the function block output and quality

 

NOTES:

  1. Function code 42 cannot connect to a function code 45 in a different Cnet loop. Use function code 122 to connect with another loop.

  2. If a module utilizes an imported digital value from the loop in several instances, the function blocks that utilize this digital value must be connected to one digital input/loop function block that handles the importation of this point. It is not possible to import exception reports from a particular address to more than one destination digital input/loop function block within a single module configuration.

 

Specifications:

Spec

Tune

Default

Type

Range

Description

S1

N

0

I

0 - 31

Requested module address

S2

N

0

I

Note 1

Requested block address

S3

N

0

I

1 - 250

Requested node address

 

NOTE:

1. Maximum values are: 9,998 for the BRC-100, IMMFP11/12 and 31,998 for the HAC.

 

42.1  Examples

 

Figure 42-1 illustrates the configuration required to test point quality. Input to a function code 42 block must come from a function code 45 block.