USA57 Revision
1.2
83
Appendix B
Device Response Packet
The Accuriss responds to commands by sending messages addressed to the “Master Device”.
The Master Device (which for example is a PC) is assumed to always have Address zero. The
master device should parse the communications on the bus continuously for responses starting
with /0. (Do NOT, for example, look for the next character coming back after issuing a
command because glitches on the bus when the bus reverses direction can sometimes be
interpreted as characters)
After the /0, the next piece of information is the “Status Character” which is actually a collection
of 8 bits.
These Bits are:
Bit7 … Reserved
Bit6 … Always Set
Bit5 … Ready Bit - Set when Accuriss is ready to accept a command.
Bit4 … Reserved
Bits 3 thru 0 form an error code from 0-15
0 = No Error
1 = InitError
2 = Bad Command (illegal command was sent)
3 = Bad Operand (Out of range operand value)
4 = N/A
5 = Communications Error (Internal communications error)
6 = N/A
7 = Not Initialized (Controller was not initialized before attempting a move)
8 = N/A
9 = Overload Error (Physical system could not keep up with commanded position)
10 = N/A
11 = Move Not Allowed
12 = N/A
13 = N/A
14 = N/A
15 = Command Overflow (unit was already executing a command when another command was
received)
Note that RS485 Bus devices must respond right away, after the master sends a command,
before the success or failure of the execution of the command is known. Due to this reason
some error messages that come back are for the previous command, for example, “failure to
find home”.