Delta Electronics VFD-VL manual Ascii mode RTU mode, A1H, Exception

Chapter 4 Parameters

3.6 Exception response:

The AC motor drive is expected to return a normal response after receiving command messages from the master device. The following depicts the conditions when no normal response is replied to the master device.

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

The AC motor drive receives the messages without a communication error, but cannot handle them. An exception response will be returned to the master device and an error message “CExx” will be displayed on the keypad of AC motor drive. The xx of “CExx” is a decimal code equal to the exception code that is described below.

In the exception response, the most significant bit of the original command code is set to 1, and an exception code which explains the condition that caused the exception is returned.

Example of an exception response of command code 06H and exception code 02H:

ASCII mode:		RTU mode:
STX	‘:’	Address	01H
Address Low	‘0’	Function	86H
Address High	‘1’	Exception code	02H
Function Low	‘8’	CRC CHK Low	C3H
Function High	‘6’	CRC CHK High	A1H
Exception code	‘0’
	‘2’
LRC CHK Low	‘7’
LRC CHK High	‘7’
END 1	CR
END 0	LF

The explanation of exception codes:

Exception

code Explanation

Illegal function code:

01The function code received in the command message is not available for the AC motor drive.

Illegal data address:

02The data address received in the command message is not available for the AC motor drive.

Illegal data value:

03The data value received in the command message is not available for the AC drive.

04Slave device failure:

The AC motor drive is unable to perform the requested action.

Communication time-out:

10If Pr.09-03 is not equal to 0.0, Pr.09-02=0~1, and there is no communication on the bus during the Time Out detection period (set by Pr.09-03), “cE10” will be shown on the keypad.

Revision Nov. 2008, VLE1, SW V1.03 4-95