Delta DVP-SS2 User Manual

4. Communications
4-5
Field name
ASCII
Hex
Data Lo (T21)
02
30 32
Data Hi (T22)
00
30 30
Data Lo (T22)
03
30 33
Data Hi (T23)
00
30 30
Data Lo (T23)
04
30 34
Data Hi (T24)
00
30 30
Data Lo (T24)
05
30 35
Data Hi (T25)
00
30 30
Data Lo (T25)
06
30 36
Data Hi (T26)
00
30 30
Data Lo (T26)
07
30 37
Data Hi (T27)
00
30 30
Data Lo (T27)
08
30 38
Check sum(LRC)
C8
43 38
END
CR LF
0D 0A
4.2.3 LRC CHK (checksum)
LRC (Longitudinal Redundancy Check) is calculated by summing up the Hex values from ADR1 to last
data character then finding the 2’s-complement negation of the sum.
Example: Read the content of register at address 0401H. 01H+03H+04H+01H+00+01H = 0AH.
The 2’s-complement of 0AH: F6H
Field name
ASCII
Hex
STX
:
3A
Slave Address
01
30 31
Command code
03
30 33
Starting data address Hi
04
30 34
Starting data address Lo
01
30 31
Number of data Hi
00
30 30
Number of data Lo
01
30 31
LRC checksum
F6
46 36
END
CR LF
0D 0A
Exception response:
The PLC is expected to return a normal response after receiving command messages from the master
device. The following table depicts the conditions that either a no response or an error response is
replied to the master device.
1. The PLC did not receive a valid message due to a communication error; thus the PLC has no
response. The master device will eventually process a timeout condition.
2. The PLC receives a valid message without a communication error, but cannot accommodate it, an

Delta DVP-SS2 Specifications

General

Brand	Delta
Model	DVP-SS2
Category	Controller
Language	English