FC 29 - Analog Output

The analog output function code sends values from controller modules fixed output blocks to termination units. The input to the block, usually from a station, must be scaled zero to 100 percent for the block to function properly over the entire span of the input signal.

 

There are only two possible outputs. The first will always be the output of the first fixed analog output block, 211. The second will be the output of fixed analog output block 212.

 

To insure that the signal is successfully transferred to the field, the analog signal generates a point quality flag. To test the quality of the signal, include a function code 31 (test quality) block in the configuration. The quality of the signal cannot be used as an input to any other type of block. However, the output of the test quality block can be used as an input to other digital processing blocks to provide signal quality information.

 

 

 

Outputs:

Blk

Type

Description

211

R

Value of analog output 1

212

R

Value of analog output 2

 

 

Use S2 (station block address) only with digital control stations that have the automatic bypass option enabled. When S2 is configured and the analog output feedback value to the station changes to bad quality, function code 29 forces the station to bypass mode.

 

Specifications:

Spec

Tune

Default

Type

Range

Description

S1

N

211

I

0 - 255

Block address of input

S2

N

0

I

0 - 255

Block address of station block associated with output

 

 

29.1  Explanation

 

Figure 29-1 illustrates the configuration required to test the quality of an analog output.