FC 114 - BCD Input

The BCD input block reads a boolean input from an IMDSI12 or IMDSI22 module in a binary coded decimal (BCD) format, and converts it to a real output with quality.

 

Outputs:

Blk

Type

Description

N

R

Real value X gain

 

 

 

Specifications:

Spec

Tune

Default

Type

Range

Description

S1

N

0

I

0 - 63

Expander bus I/O module address of digital I/O module

S2

N

1

I

1 - 4

Zone containing ones digit of output:

1 and 2 = zones reside in group B

3 and 4 = zones reside in group A

 

Input number on I/O module:

1 = 1 to 4 (B) (S4 can be any value)

2 = 5 to 8 (B) (S4 must be =<3)

3 = 1 to 4 (A) (S4 must be =<2)

4 = 5 to 8 (A) (S4 must be set to 1)

S3

N

0

I

0 or 1

Module action on I/O module failure:

0 = trip control module

1 = continue operation

S4

N

1

I

1 - 4

Number of digits in converted value

S5

N

1.000

R

Full

Gain multiplier

 

 

 

114. 1  Explanation

 

 Each I/O module provides 16 inputs divided into two groups of eight as illustrated in Table 114-1. The two groups are divided into four zones, with each zone containing four inputs.

 

 

Figure 114-1 shows the binary coding of the four inputs in each zone. The boolean values convert internally to BCD values from zero to nine. A true input for any character in a zone causes the integer number associated with that character to be output. If the inputs of a zone are 0 1 1 1, the output is 4+2+1=7. BCD values greater than nine are invalid since each zone provides only one digit of the output value.

 

 

Specification S2 selects the zone that the ones digit of the BCD value will be read from. This arrangement enables a two digit integer to convert to only one group of inputs from any given I/O module, freeing the other inputs for other configuration uses. Specification S4 sets the number of digits the integer internally generates. Specifications S2 and S4 define the size and location of the integer.

 

114.1.1 Specifications

 

S1 - SLVADR

Expander bus I/O module address of the digital input I/O module that carries inputs to be converted. Valid addresses are zero to 63.

 

S2 - ZONE

Sets the zone containing the ones digit of the output. Zones three and four reside in group A, and zones one and two reside in group B.

 

S3 - TRIP

Defines the action of the control module on I/O module failure.

0 = trip control module

1 = continue operating

 

S4 - DNUM

Number of digits in converted value (one to four).

 

S5 - K

Gain multiplier. This real value is multiplied by the integer number generated by the conversion to provide a real output used

for control purposes.

 

 

114.1.2  Outputs

 

N

Binary coded decimal value times gain, and quality.

 

 

114.2  Example

 

If the inputs to the BCD input function block are:

S2 = 1. Ones digit is found in zone 1.

S4 = 3. Output value is three digits (zones 1, 2 and 3).

S5 = 1.0. Gain is 2.0.

 

Then, the inputs to the I/O module are:

 

 

Integer value = 385

Output value = 385 x 2.0 = 770.0

 

NOTE: Even though some of the inputs in zone four are true (logic 1), the conversion does not use them (S2 equals one and S4 equals three).