Status Codes; Handshaking Procedure - GE D485 Instruction Manual

STATUS CODES

HANDSHAKING
PROCEDURE
D485 MODBUS TO DEVICENET CONVERTER – USER GUIDE
The status codes are described in the following table.
Code Error
0x00 Re-transmission
0x01 Single node missing
0x02 Multiple nodes
missing
0x03 Overrun
0x04 Other error
0x1F No error
The handshake bits are used to indicate any changes in the status and control registers.
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
Start
Compare CR_HS_CONFIRM with
SR_HS_SEND
Equal?
Yes
No
Read Status Register
Set CR_HS_CONFIRM to
SR_HS_SEND
End
Description
Number of re-transmissions. Reports the total number of
re-transmissions on the subnetwork
Slave address of the missing node. Reports if a node is
missing
Number of missing nodes. Reports if multiple nodes are
missing
Slave address of the node that sent too much data.
Reports if more data than expected was received from a
node
Slave address. Reports unidentified node
Normal Condition
No
Figure 8-1: Handshaking flowchart
ADVANCED FUNCTIONS
Control Register Writes
Start
Compare SR_HS_CONFIRM with
CR_HS_SEND
Equal?
Yes
Write to Control Register
Toggle CR_HS_SEND
End
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