GE P485 instruction manual Handshake bits themselves bits 14, Code Error Description

ADVANCED FUNCTIONS

STATUS CODES The status codes are described in the following table.

Code	Error	Description
0x00	Re-transmission	Number of re-transmissions. Reports the total number of
		re-transmissions on the subnetwork
0x01	Single node missing	Slave address of the missing node. Reports if a node is
		missing
0x02	Multiple nodes	Number of missing nodes. Reports if multiple nodes are
	missing	missing
0x03	Overrun	Slave address of the node that sent too much data.
		Reports if more data than expected was received from a
		node
0x04	Other error	Slave address. Reports unidentified node
0x1F	No error	Normal Condition

HANDSHAKING The handshake bits are used to indicate any changes in the status and control registers. PROCEDURE The procedure below must be followed for all changes to these registers with the exception

of the handshake bits themselves (bits 14 and 15).

Status Register Reads	Control Register Writes
Start	Start

Compare CR_HS_CONFIRM with SR_HS_SEND

Equal?

Yes

Compare SR_HS_CONFIRM with CR_HS_SEND

Equal?

No

No

Yes

Read Status Register

Write to Control Register

Set CR_HS_CONFIRM to SR_HS_SEND

End

Toggle CR_HS_SEND

End

Figure 8-1: Handshaking flowchart

P485 MODBUS TO PROFIBUS CONVERTER – USER GUIDE 8–3