FC 79 - Control Interface Slave

Use the control interface slave function code to interface a Harmony controller to a control I/O module. Control I/O modules have four analog inputs, two analog outputs, three digital inputs, and four digital outputs. This function code defines the characteristics of that I/O module and how the system responds to an I/O module failure.

 

 

Outputs:

 

Blk

Type

Description

N

R

Analog Input 1

N+1

R

Analog Input 2

N+2

R

Analog Input 3

N+3

R

Analog Input 4

N+4

R

Analog output 1 feedback

N+5

R

Analog output 2 feedback

N+6

B

Digital Input 1

N+7

B

Digital Input 2

N+8

B

Digital Input 3

N+9

B

I/O module status flag:

0 = good

1 = bad

 

 

 

The control system must be carefully evaluated to establish

default values that will prevent personal injury and/or property

damage in case of module failure.

 

 

 

Specifications:

Spec

Tune

Default

Type

Range

Description

S1

N

0

I

0 - 63

Control interface I/O module address

S2

N

0.000

R

Full

Analog input 1 zero in engineering units

S3

N

0.000

R

Full

Analog input 1 span in engineering units

S4

N

0.000

R

Full

Analog input 2 zero in engineering units

S5

N

0.000

R

Full

Analog input 2 span in engineering units

S6

N

0.000

R

Full

Analog input 3 zero in engineering units

S7

N

0.000

R

Full

Analog input 3 span in engineering units

S8

N

0.000

R

Full

Analog input 4 zero in engineering units

S9

N

0.000

R

Full

Analog input 4 span in engineering units

S10

N

2

I

0 - 31,999

Block address of analog output 1

S11

N

2

I

0 - 31,999

Block address of analog output 2

S12

N

2

I

0 or 1

Digital input 1 logic sense

S13

N

2

I

0 or 1

Digital input 2 logic sense

S14

N

2

I

0 or 1

Digital input 3 logic sense

S15

N

2

I

0 - 31,999

Block address of digital output 1

S16

N

2

I

0 - 31,999

Block address of digital output 2

S17

N

2

I

0 - 31,999

Block address of digital output 3

S18

N

2

I

0 - 31,999

Block address of digital output 4

S19

N

0

I

0 or 1

Failure action (lack of I/O module response or bad analog input reference voltage):

XX0 = trip module

XX1 = continue to operate

 

I/O module status flag (bad status indication):

0XX = set I/O module status flag output N+9 to bad when the  CIS module fails or is in error mode

 

1XX = set I/O module status flag output N+9 to bad when the I/O module fails or there is a bad quality on one of the module's I/O points

 

 

79.1 Explanation

 

79.1.1 Outputs

 

This block provides analog and digital I/O on the same board. The final output is an I/O module status flag, which shows the status of the control I/O module.

0 = good

1 = bad

 

Analog output feedbacks (N+4 and N+5) provide feedback to M/A stations (function code 80) that have hardware stations with bypass capabilities. This feedback signal provides an alignment reference for the software logic, before establishing control of the process when exiting from bypass or configure mode (bumpless transfer).

 

NOTE: If S19 equals zero, and if there is a bad or unwired input, then the control module is tripped.

 

79.1.2 Specifications

 

S1 - IOSLV

(Control I/O module address) I/O module address set by the address dipswitch on the I/O module. Available addresses are zero through 63.

 

S2 to S9

(AIZn and AISPn) Set the zero and span values for four analog inputs. If an analog value goes below the zero value or exceeds the span by more than five percent, it will produce a bad quality output. A specified span other than zero (default) for an unused analog input produces a bad quality signal for that input.

 

S10 - AO1

Block address of input for analog output one

 

S11 - AO2

Block address of input for analog output two.

 

S12 to S14 - DIn

Set the logic sense for three digital inputs. Digital inputs can be defined for direct or reverse acting logic operations. These are defined as follows:

0 = reverse acting (logic 0 = closed, logic 1 = open)

1 = direct acting (logic 0 = open, logic 1 = closed)

2 = unused input

 

S15 to S18 - DOn

Block addresses of the inputs for the four digital outputs.

 

S19 - FAIL

Value defines the module response in case of control I/O module failure. Lack of I/O module response or a bad analog input reference voltage will cause a transfer to error mode.

 

Specification S19 also determines which failure conditions cause the I/O module status flag output N+9 to go to logic 1(bad).