Plc Delta

DELTA DVP Series PLC

COMMUNICATION PROTOCOL VER 1.0

1. Communication Interface: RS-232C

2. Communication Protocol ASCII mode, 9600（Baud rate）,7(Data length), EVEN（Parity）,1（Stop bit）

3. Communication Data Frame

STX Start character ‘:’（3AH）

ADR 1 Communication address:

ADR 0 8-bit address consists of 2 ASCII codes

CMD 1 Command code:

CMD 0 8-bit command consists of 2 ASCII codes

DATA（0） Contents of data:

DATA（1） n8-bit data consist of 2n ASCII codes.

………. n37, maximum of 74 ASCII codes

DATA（n-1）

LRC CHK 1 LRC check sum:

LRC CHK 0 8-bit check sum consists of 2 ASCII codes

END 1 End character:

END 0 END 1 = CR（0DH），END 0 = LF（0AH）

 ADR（Communication Address）

Valid communication addresses are in the range of 0…31. Communication address equals to 0 means broadcast to all PLC, the PLC will reply normal message to the master device.

For example, communication to PLC with address 16 decimal:

(ADR 1, ADR 0)=’1’,’0’’1’=31H, ‘0’ = 30H

 CMD (Command code) and DATA (data characters)

The format of data characters depends on the command code. For example, reading continuous 8 words form starting device address 0614H of PLC with address 01H.

Field Name Example (Hex)

Heading 3A

Slave Address 01

Command code 03

Starting Address Hi 06

Starting Address Lo 14

Number of Points Hi 00

Number of Points Lo 08

Error Check ( LRC ) DA

Number of Points(max)

= 18（for 16 bit register）

= 9（for 32 bit register）

Example：Reading Coils T20~T27 from slave device 01

PC→PLC

“：01 03 06 14 00 08 DA CR LF”

PLC→PC

“：01 03 10 00 01 00 02 00 03 00 04 00 05 00 06 00 07 00 08 B8 CR LF”

Field Name Example (Hex)

Slave Address 01

Command code 03

Bytes Count 10

Data Hi（T20） 00

Data Lo（T20） 01

Data Hi（T21） 00

Data Lo（T21） 02

Data Hi（T22） 00

Data Lo（T22） 03

Data Hi（T23） 00

Data Lo（T23） 04

Data Hi（T24） 00

Data Lo（T24） 05

Data Hi（T25） 00

Data Lo（T25） 06

Data Hi（T26） 00

Data Lo（T26） 07

Data Hi（T27） 00

Data Lo（T27） 08

Error Check（LRC） C8

 LRC CHK（check sum）

LRC (Longitudinal Redundancy Check) is calculated by summing up, module 256, the values of the bytes from ADR1 to last data character then calculating the hexadecimal representation of the 2’s-complement negation of the sum.

For example, reading 1 word form address 0401H of the PLC with address 01H

STX ‘：’

ADR 1 ‘0’

ADR 0 ‘1’

CMD 1 ‘0’

CMD 0 ‘3’

Starting data address ‘0’

‘4’

‘0’

‘1’

Number of data ‘0’

‘0’

‘0’

‘1’

LRC CHK 1 ‘F’

LRC CHK 0 ‘6’

END 1 CR

END 0 LF

01H+03H+04H+01H+00+01H = 0AH

the 2’s-complement negation of 0AH is F6H

Exception response:

The PLC is been expected to return a normal response after receiving command messages from the master device. The following depicts the conditions that no normal response is replied to the master device.

The PLC does not receive the messages due to a communication error; thus the PLC has no response. The master device will eventually process a timeout condition.

The PLC receives the messages without a communication error, but cannot handle it, an exception response will return to the master device. In the exception response, the most significant bit of the original command code is set to 1, and an exception code explains the condition that caused the exception is returned.

An example of exception response of command code 01H and exception 02H:

Command message:

Field Name Example (Hex)

Heading 3A

Slave Address 01

Function 01

Starting Address Hi 04

Starting Address Lo 00

Number of Points Hi 00

Number of Points Lo 10

Error Check ( LRC ) EA

Response message:

Field Name Example (Hex)

Heading 3A

Slave Address 01

Function 81

Exception Code 02

Error Check ( LRC ) 7C

Exception code: Meaning:

01 Illegal command code:

The command code received in the command message is not available for the PLC.

02 Illegal device address:

The device address received in the command message is not available for the PLC.

03 Illegal device value:

The device value received in the command message is not available for the PLC.

07 Check Sum Error

Check if the check Sum is correct

Illegal command messages

The command message is too short.

Command message length is out of range.

 The format of data characters depends on the command. The available command codes are described as followed,

Code Name Description

01 Read Coil Status S, Y, M, T, C

02 Read Input Status S, X, Y, M,T, C

03 Read Holding Registers T, C, D

05 Force Single Coil S, Y, M, T, C

06 Preset Single Register T, C, D

15 Force Multiple Coils S, Y, M, T, C

16 Preset Multiple Register T, C, D

17 Report Slave ID None

DELTA DVP-ES Series PLC DEVICE ADDRESS

Device

Range Effective Range Address

S 000~255 000~127 0000~00FF

S 246~511 0100~01FF

S 512~767 0200~02FF

S 768~1023 0300~03FF

X 000~377 (Octal) 000~177 (Octal) 0400~04FF

Y 000~377 (Octal) 000~177 (Octal) 0500~05FF

T 000~255 000~127 0600~06FF

M 000~255 0000~1279 0800~08FF

M 256~511 0900~09FF

M 512~767 0A00~0AFF

M 768~1023 0B00~0BFF

M 1024~1279 0C00~0CFF

C 000~255 000~127

232~255 0E00~0EFF

D 000~255 000~599

1000~1143 1000~10FF

D 256~511 1100~11FF

D 512~767 1200~12FF

D 768~1023 1300~13FF

D 1024~1279 1400~14FF

Command Code：01, Read Coil Status

Field Name Example (Hex)

Heading 3A

Slave Address 01

Command code 01

Starting Address Hi 06

Starting Address Lo 14

Number

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