DVP-ES2-EX2-SS2-SA2-SX2-Operation Manual

4. Communications
4.5 Command Code
4.5.1 Command Code: 01, Read Status of Contact (Input point X is not included)
Number of Points (max) = 255 (Dec) = FF (Hex)
Example:Read contacts T20~T56 from Slave ID#1
PC→PLC “:01 01 06 14 00 25 BF CR LF”
Sent message:
Field Name
ASCII
STX :
Slave Address 01
Command code 01
Starting Address Hi 06
Starting Address Lo 14
Number of Points Hi 00
Number of Points Lo 25
Error Check (LRC)
ETX 1
ETX 0
BF
0D (Hex)
0A (Hex)
Assume Number of Points in sent message is n (Dec), quotient of n/8 is M and the remainder is N.
When N = 0, Bytes Count in feedback message will be M; when N≠0, Bytes Count will be M+1.
PLC→PC “:01 01 05 CD 6B B2 0E 1B D6 CR LF”
Feedback message:
Field Name
ASCII
STX :
Slave Address 01
Command code 01
Bytes Count 05
Data (Coils T27…T20)
Data (Coils T35…T38)
Data (Coils T43…T36)
Data (Coils T51…T44)
Data (Coils T56…T52)
Error Check (LRC)
END 1
END 0
CD
6B
B2
0E
1B
E6
0D (Hex)
0A (Hex)
4-13