B&B Electronics RS-485 manual Syntax, Reading A/D Channels Command, Equivalent Values

Page 17

The decimal and hexadecimal equivalents of some ASCII characters are shown in Table 3.2. Notice that the ASCII representation of the character “0” does not have a value of 0. Refer to Appendix C for more ASCII, decimal, and hexadecimal equivalents.

Table 3.2 - Equivalent Values

ASCII

Decimal

Hexadecimal

 

 

 

!

33

21h

0

48

30h

A

65

41h

D

68

44h

O

79

4Fh

R

82

52h

S

83

53h

NUL

0

0h

SOH

1

1h

STX

2

2h

ETX

3

3h

EOT

4

4h

ENQ

5

5h

ACK

6

6h

BEL

7

7h

Syntax

The command string consists of four bytes. The first byte is the start of message byte. The start of message byte is always the “!” character. The second byte is the address byte. This byte allows each unit to have a unique address. The factory default address is the ASCII “0” (zero) character. The next two bytes are the command characters. These bytes are used to specify which command the module will execute. The read A/D and digital I/O commands require an additional data byte.

Command Syntax: !

 

_

_

_

Data Byte

2nd Command Byte

1stCommand Byte

Address Byte

 

Start of Message Byte

 

Reading A/D Channels Command

485SDA103798 Manual

13

B&B Electronics -- 707 Dayton Rd. --

PO Box 1040 -- Ottawa, IL 61350

PH (815) 433-5100 --

FAX (815) 434-7094

Image 17 Contents
Internet Electronics Mfg. Co. IncDesigned and Manufactured Ottawa, Illinois Table of Contents Tables Software485SDA103798 Manual Table of Contents Iii 485SDA10 Unit 485SDA10 FeaturesPacking List Software InstallationGetting Started UninstallWindows Windows 9x and Windows NTA/D with Variable Resistor 485SDA10 Specifications Ref Input + Inputs #0-10Typical Connections Ref InputAnalog Ground 485SDA10 I/O Port Pinout Digital I/O ConnectionsDigital Inputs #0-2 Digital Outputs #0-2Typical Digital I/O Connections Digital GroundRS-485 Terminal Block Connections Serial Port ConnectionsTypical RS-485 2-wire Connection Power Supply Connections485SDA10 Commands CommandsEquivalent Values Reading A/D Channels CommandSyntax Read A/D Response AddrRA#Ch#MSBch#LSBch#-1MSB...ch0MSBch0LSB AddrRD Reading Digital I/O CommandStates Read Digital I/O Response for OutputsSet Module Address Command Set Digital Output CommandAddrSOstates Set Digital Output Data Byte ValuesRead Module Configuration Command Set Power-up States CommandSet Turn-around Delay Command Addressstatesdelay Reference Inputs Sampling RateInput Range Converting Data Data RangePage Command$ = ! + CHR$addr + RA + CHR$channel Read A/D CommandPrint #1, Command$ MSB$ = INPUT$1, #1 LSB$ = INPUT$1, #1Reply$ = INPUT$ 1, #1 Read Digital I/O CommandCommand$ = ! + CHR$addr + RD Digital I/O Mask Values Set Digital Output StatesCommand$ = ! + CHR$addr + SO + CHR$newaddr Command$ = !0SO + CHR$statesSet Module Address Addr =Addr = 5 states = States = states and NOTmaskCommand$ = ! + CHR$addr + SC + CHR$delay Set Turn-around DelayRead Module Configuration Comp = not x and &HFF #addrRA00FF00FF01FE Table A-1 Extended Commands Appendix B Analog Input Impedance 1 2 LSB = R s + 1k Ω × 60pF × ln2048 Simplified Analog Input Analysis485SDA103798 Manual Appendix B Table C-1 Decimal to HEX to Ascii Table Appendix C Decimal to HEX to Ascii TableClass a Equipment
Related manuals
Manual 39 pages 36.61 Kb Manual 46 pages 1.37 Kb