Modbus Protocols Error Code P499 Explanation; Automationdirect Click; Automationdirect Directlogic - Modbus (Koyo; Modicon Modbus Rtu - C-more micro EA1-S6ML Hardware User Manual

Appendix A: Panel & PLC Error Code Tables
C-more Micro-Graphic Panel Error Code Table (cont'd)
A
Error Code Error Message
ErrCode Received ->
P499*
Recv .Err Code XXXX
P500 Can'tWriteS.Port
P700 RD.Buff.MEM Full
P701 INV.PLC Address
P702 INV.FUN.Code
P703 WRT.PLC.ReadOnly

Modbus Protocols Error Code P499 Explanation

The following table lists the errors that can be generated by the Modbus protocols:

AutomationDirect CLICK

AutomationDirect DirectLOGIC - Modbus (Koyo)

Modicon Modbus RTU

Entivity Modbus RTU

Note: The following errors can be generated from the designated PLC, are monitored by the C-more Micro-
Graphic panel, and displayed on the panel's screen as a hexadecimal value in panel error code P499, if active.
Panel Error
Code
ILLEGAL
0x0001
FUNCTION
ILLEGAL DATA
0x0002
ADDRESS
ILLEGAL DATA
0x0003
VALUE
SLAVE DEVICE
0x0004
FAILURE
A–4
C-more Micro-Graphic Panel Error Table (cont'd)
A PLC generated error code with a hexadecimal value of XXXX has been returned from the
PLC. * See the explanation for error code P499 proceeding each set of PLC error code tables.
Data cannot be written to the Serial port.
Data was sent to the PLC via the Serial Port.
If this error shows on the Panel, it indicates a Hardware Problem.
There was an error while allocating memory for the read buffer. When this error is displayed, a
memory leak may have occurred.
Request to inaccessible memory from the HMI layer to the PLC protocol layer. This error is an
indication that there is a problem in the HMI layer.
A Read/Write/SetBit request has been sent to an invalid memory area. This error is an
indication that there is a problem in the HMI layer.
A PLC Write request was made to the PLC's Read-Only memory area.This error is an indication
that there is a problem in the HMI layer or the PLC protocol layer.
PLC Error Codes Modbus Protocols
Name
The function code received in the query is not an allowable action for the server (or slave). This
may be because the function code is only applicable to newer devices and was not
implemented in the unit selected. It could also indicate that the server (or slave) is in the wrong
state to process a request of this type, for example because it is unconfigured and is being
asked to return registered values.
The data address received in the query is not an allowable address for the server (or slave).
More specifically, the combination of reference number and transfer length is invalid. For a
controller with 100 registers, the PDU addresses the first register as 0, and the last one as 99.
If a request is submitted with a starting register address of 96 and a quantity of registers of 4,
then the request will successfully operate (address-wise at least) on registers 96, 97, 98, 99. If
a request is submitted with a starting register of 96 and a quantity of registers of 5, then the
request will fail with Exception code 0x02 "Illegal Data Address" since it attempts to operate on
registers 96, 97, 98, 99 and 100, and there is no register with address 100.
A value contained in the query data field is not an allowable value for server (or slave). This
indicates a fault in the structure of the remainder of a complex request, such as that the implied
length is incorrect. It specifically does NOT mean that a data item submitted for storage in a
register has a value outside the expectation of the application program, since the Modbus
protocol is unaware of the significance of any particular value of any particular register.
An unrecoverable error occurred while the server (or slave) was attempting to perform the
requested action.
® EA1-MG6-USER-M Hardware User Manual, 1st Ed. Rev C, 09/10
Cause
Meaning