Bedienungsanleitung Elm 327 (Seite 18 von 94) (Englisch)

612699

Zoom out

Zoom in

Vorherige Seite

1/94

Nächste Seite

FI [ perform a Fast Initiation ]

One version of the Keyword protocol uses what is

known as a 'fast initiation' sequence to begin

communications. Usually, this sequence is performed

when the first message needs to be sent, and then the

message is sent immediately after. Some ECUs may

need more time between the two however, and having

a separate initiation command allows you to control

this time. Simply send AT FI, wait a little, then send the

message. You may need to experiment to get the right

amount of delay.

Another use for this command might be if you

would like to perform a fast initiation with an ISO 9141

type protocol (ie 3 - CARB format). Simply follow these

steps to do that:

AT SP 5

AT FI

AT SP 3

AT BI

and you should be able to then communicate with the

ECU. Note that a protocol close (ie AT PC) is not

required in the above code, as the ELM327

automatically performs one when you switch protocols.

Protocol 5 must be selected to use the AT FI

command, or an error will result.

H0 and H1 [ Headers off or on ]

These commands control whether or not the

additional (header) bytes of information are shown in

the responses from the vehicle. These are not

normally shown by the ELM327, but may be of interest

(especially if you receive multiple responses and wish

to determine what modules they were from).

Turning the headers on (with AT H1) actually

shows more than just the header bytes – you will see

the complete message as transmitted, including the

check-digits and PCI bytes, and possibly the CAN data

length code (DLC) if it has been enabled with PP 29 or

AT D1. The current version of this IC does not display

the CAN CRC code, nor the special J1850 IFR bytes

(which some protocols use to acknowledge receipt of a

message).

I [ Identify yourself ]

Issuing this command causes the chip to identify

itself, by printing the startup product ID string (currently

‘ELM327 v2.1’). Software can use this to determine

exactly which integrated circuit it is talking to, without

having to reset the IC.

IB 10 [ set the ISO Baud rate to 10400 ]

This command restores the ISO 9141-2 and

ISO 14230-4 baud rates to the default value of 10400.

IB 48 [ set the ISO Baud rate to 4800 ]

This command is used to change the baud rate

used for the ISO 9141-2 and ISO 14230-4 protocols

(numbers 3, 4, and 5) to 4800 baud, while relaxing

some of the requirements for the initiation byte

transfers. It may be useful for experimenting with some

vehicles. Normal (10,400 baud) operation may be

restored at any time with the IB 10 command.

IB 96 [ set the ISO Baud rate to 9600 ]

This command is used to change the baud rate

used for the ISO 9141-2 and ISO 14230-4 protocols

(numbers 3, 4, and 5) to 9600 baud, while relaxing

some of the requirements for the initiation byte

transfers. It may be useful for experimenting with some

vehicles. Normal (10,400 baud) operation may be

restored at any time with the IB 10 command.

IFR0, IFR1, and IFR2 [ IFR control ]

The SAE J1850 protocol allows for an In-Frame

Response (IFR) byte to be sent after each message,

usually to acknowledge the correct receipt of that

message. The ELM327 automatically generates and

sends this byte for you by default, but you can override

this behaviour with this command.

The AT IFR0 command will disable the sending of

all IFRs, no matter what the header bytes require.

AT IFR2 is the opposite - it will cause an IFR byte to

always be sent, no matter what the header bytes say.

The AT IFR1 command is the default mode, with the

sending of IFRs determined by the ‘K’ bit of the first

header byte (for both PWM and VPW).

IFR H and IFR S [ IFR from Header or Source ]

The value sent in the J1850 In-Frame Response

(IFR) byte is normally the same as the value sent as

the Source (or Tester) Address byte that was in the

header of the request. There may be occasions when

it is desirable to use some other value, however, and

this set of commands allows for this.

18 of 94

ELM327

ELM327DSJ Elm Electronics – Circuits for the Hobbyist

www.elmelectronics.com

AT Command Descriptions (continued)

Missbrauch melden von Frage und/oder Antwort

Libble nimmt den Missbrauch seiner Dienste sehr ernst. Wir setzen uns dafür ein, derartige Missbrauchsfälle gemäß den Gesetzen Ihres Heimatlandes zu behandeln. Wenn Sie eine Meldung übermitteln, überprüfen wir Ihre Informationen und ergreifen entsprechende Maßnahmen. Wir melden uns nur dann wieder bei Ihnen, wenn wir weitere Einzelheiten wissen müssen oder weitere Informationen für Sie haben.

Elm 327 Seite 18

Brauchen Sie Hilfe? Stellen Sie Ihre Frage.

Missbrauch melden von Frage und/oder Antwort

Art des Missbrauchs:

Forenregeln

Neu registrieren

Das Handbuch wird per E-Mail gesendet. Überprüfen Sie ihre E-Mail.

Ihre Frage wurde zu diesem Forum hinzugefügt

Info