3 - Software Communication
Communication Protocols
Cavro® XLP 6000 Modular Syringe Pump Operating Manual, 734237-C, en
3 - 17
<DLC>
4-bit data length code
<Answer>
Data bytes block. The first byte of the data block is always the status byte,
which is an error code (same error codes used with the RS232 and RS485
protocols) added to Ox20h. The second byte is always Ox60h. The remaining
bytes contain the response in ASCII format. If the reply consists of more than
six bytes, the multi-frame messages are used.
Note: Only one command of a given frame type can be in progress at any one
time; e.g., after issuing a command to a slave pump with frame type = 1, the
master must wait for the answer with frame type = 1 before issuing the next
command with frame type = 1. If the user insists on sending the command, a
command overload status results.
Several commands with different frame types can be in progress at the same
time; e.g., an action command and a query command.
Following are typical exchanges between the host and slave for action
commands, multi-frame commands, common commands, and query commands.
Action Command
The host commands [ZR] to a pump, and the pump is set to address 0.
Note: The mixed formats ASCII and hexadecimal are used in the data bytes
block. The hexadecimal number is bracketed (< >). The rest of the fields are
displayed in binary format.
Host sends:
0
XXXXXXX
001
0
0010
ZR
Dir
Slave ID
Frame Type
RTR
DLC
Data bytes
Pump acknowledges:
1
XXXXXXX
001
0
0000
Dir
Slave ID
Frame Type
RTR
DLC
After executing the command, pump reports status:
1
XXXXXXX
001
0
0010
<20h><60h>
Dir
Slave ID
Frame Type
RTR
DLC
Data bytes