FP_ENCODE

Encode bit state -> hexadecimal

This FP instruction encodes the contents of data specified by s1_Start according to the contents of s2_Control if the trigger EN is TRUE. The encoded result is stored in the 16-bit destination area specified by d_Start starting with the specified bit position. Invalid bits in the area specified for the encoded result are filled with zeros.

FP_ENCODE is the inverse instruction of FP_DECODE.

Parameters

Input

s1_Start (WORD): Starting 16-bit area to be encoded (source)
s2_Control (WORD): Control data to specify the starting bit position and number of bits to be encoded

Output

d_Start (WORD): 16-bit area for storing encoded data (destination)

Remarks

The variables s1_Start, s2_Control and d_Start have to be of the same data type.

Example with s2_Control=16#0005

16#

↑

Number of bits to be encoded: 2⁵=32 bits

Starting bit position of the data to be encoded: bit position 0

(1) Source
(2) Bit position
(3) 32 bits as specified by 16#0005
(4) The 8^th bit of 32-bit data is TRUE.
(5) Destination
The encoded result 8 (decimal) is stored in d_Start when the trigger EN is TRUE.
(6) Starting bit position
(7) Bit position 8–15 are filled with zeros.
(8) Encoded result: 8

Description of the process

The contents of the 2^nL bit segment at the beginning of the area specified by s1_Start is encoded (where nL is the number of bits to be encoded).

The encoded result is stored as decimal data in the eight bits starting from the bit specified as the nH bit (where nH is the conversion start bit). Invalid bits in the specified area for the result are filled with zeros.

Description of s2_Control

s2_Control specifies the starting bit position of the destination data and the number of bits to be encoded using hexadecimal data.

(1) 16-bit data (2) Number of bit 0–15 The bits marked "-" are invalid.
	Set value 16#0–16#F	(3) Starting bit position of encoded destination data	Set value 16#0–16#8	(4) Number of encoded bits
	16#0	0	16#1	2
	16#1	1	16#2	4
	16#2	2	16#3	8 (1 byte)
	16#3	3	16#4	16 (1 word)
	16#4	4	16#5	32 (2 words)
	16#5	5	16#6	64 (4 words)
	16#6	6	16#7	128 (8 words)
	16#7	7	16#8	256 (16 words)
	16#8	8
	16#9	9
	16#A	10
	16#B	11
	16#C	12
	16#D	13
	16#E	14
	16#F	15

Encoded example

When encoding 16-bit data (nL=4), the encoded results are as shown below.

Data to be encoded (4 bits)	Encoded result
Data to be encoded (4 bits)	Hex.	Dec.
0000 0000 0000 0001	16#0000	0
0000 0000 0000 0010	16#0001	1
0000 0000 0000 0100	16#0010	2
0000 0000 0000 1000	16#0011	3
0000 0000 0001 0000	16#0100	4
0000 0000 0010 0000	16#0101	5
0000 0000 0100 0000	16#0110	6
0000 0000 1000 0000	16#0111	7
0000 0001 0000 0000	16#1000	8
0000 0010 0000 0000	16#1001	9
0000 0100 0000 0000	16#1010	10
0000 1000 0000 0000	16#1011	11
0001 0000 0000 0000	16#1100	12
0010 0000 0000 0000	16#1101	13
0100 0000 0000 0000	16#1110	14
1000 0000 0000 0000	16#1111	15

Error flags

sys_bIsOperationErrorHold (turns to TRUE and remains TRUE)

if the area specified using the index modifier exceeds the limit.
if 1 £ nL £ 8, where nL is the number of bits to be encoded/decoded.
if 1 £ nH + nL £ 16, where nH is the conversion start bit and nL is the number of bits to be encoded/decoded.
if the data to be encoded is all zero.

sys_bIsOperationErrorNonHold (turns to TRUE for one scan)

if the area specified using the index modifier exceeds the limit.
if 1 £ nL £ 8, where nL is the number of bits to be encoded/decoded.
if 1 £ nH + nL £ 16, where nH is the conversion start bit and nL is the number of bits to be encoded/decoded.
if the data to be encoded is all zero.

Example

POU header

All input and output variables used for programming this function have been declared in the POU header. The same POU header is used for all programming languages.

	VAR
		bStart: BOOL:=FALSE;
			(*activates the function*)
		wInput_value: WORD:=2#0000000001000000;
		wControlCode: WORD:=16#0003;
			(*specifies the encodation*)
		wOutput_value: WORD:=0;
			(*result after a 0->1 leading
edge from start:
2#0000000000000110*)
	END_VAR

POU body

When the variable bStart is set to TRUE, the function is carried out.

LD body

BODY
    WORKSPACE
        NETWORK_LIST_TYPE := NWTYPELD ;
        ACTIVE_NETWORK := 0 ;
    END_WORKSPACE
    NET_WORK
        NETWORK_TYPE := NWTYPELD ;
        NETWORK_LABEL :=  ;
        NETWORK_TITLE :=  ;
        NETWORK_HEIGHT := 5 ;
        NETWORK_BODY
B(B_CONTACT,,bStart,6,1,8,3,);
B(B_VARIN,,wInput_value,10,2,12,4,);
B(B_VARIN,,wControlCode,10,3,12,5,);
B(B_VAROUT,,wOutput_value,20,2,22,4,);
B(B_F,FP_ENCODE!,,12,0,20,5,,?DEN?Ds1_Start?Ds2_Control?AENO?Cd_Start);
L(1,2,6,2);
L(8,2,12,2);
L(1,0,1,5);
        END_NETWORK_BODY
    END_NET_WORK
END_BODY

ST body

IF bStart then
    FP_ENCODE(s1_Start := wInput_value, 
              s2_Control := wControlCode, 
              d_Start => wOutput_value);
END_IF;