User Manual

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TITLE

DRAWING

NO.

Communication Protocol

Specification

For

SCIP2.0

C-42-03320B

9/25

7. Communication Format

Sensor and host exchange data using set of predefined commands. These commands have specific format

known as communication format. Figure 8 and 9 shows the basic communication format between host and

sensor in SCIP2.0. Communication is initiated form host by sending a Command that consists of

Command-Symbol, Parameter, String Characters followed by line feed or carriage return or both. When sensor

receive commands it sends Reply with the Command Echo, status, sum, line feed, data related to the command,

sum and two continuous line feed as a termination code.

(HOST → SENSOR)

Command Symbol Parameter

String Characters

(Max. 16 letters)

Line Feed(LF) or Carriage Return(CR) or Both

(SENSOR → HOST)

 Command Symbol is 2 bytes code at the beginning of every command. Each command has specific

symbols for verification.

 Parameter is information that is required to change sensor settings or to request the additional data.

 String Characters are optional information in the command. They are used to verify the reply when same

command is repeated more than once, such as by sending different String Characters in each command and

checking the command echo. Maximum length of the String Characters is 16-letters made with

combination of any English letters, numbers, blank space and symbols ‘.’, ‘_’, ‘+’, ‘@’. They must be

separated by semicolon- ‘;’ -at the beginning to separate from parameter.

 Line Feed (LF) or Carriage Return (CR) is terminating code. Command can have LF or CR or both as

termination code but reply will always have two continuous LF as its termination code.

 Status is 2 bytes data in the reply that informs normal processing if command is authenticated or errors if

undefined, invalid or incomplete command is received by sensor. Status other than 00 and 99 are error

codes

 Sum is 1 byte data used in authentication. It is calculated by adding data between two linefeeds, taking the

lower 6 byte of this sum and finally adding 30H to this sum.

Example:

[LF] Hokuyo [LF] = 48H+6fH+6bH+75H+79H+6fH = 27fH = 1001 111111

Sum = 111111

= 3fH+30H = 6fH = o

 Data is main information related to the command. It is separated by LF and sum after every 64 bytes if

exceeds 64 bytes.

 IMPORTANT: $(24H) is a reserved letter for special mode. Do not use it in the commands.

Command Symbol

Parameter

String Characters

Status

Sum

Data

Sum

Command

Echo