User`s manual

Watlow Controls Communications Guide 16
Packet returned by controller: | nn | 10 | nn nn | 00 01 | nn nn |
controller address (one byte)
write to multiple registers command (0x10)
starting register high byte
starting register low byte
number of registers to write high byte (0x00)
number of registers to write low byte (must be 0x01)
CRC low byte
CRC high byte
Loop Back Command (0x08)
This command simply echoes the message. This serves as a quick way to check
your wiring.
Packet sent to controller:| nn | 08 | nn nn | nn nn |
controller address (one byte)
loop back command (0x08)
data high byte
data low byte
CRC low byte
CRC high byte
Example:
Run loop back test on controller at address 40 (0x28).
Sent: 28 08 55 66 77 88 31 B7
Received: 28 08 55 66 77 88 31 B7
Exception Responses
When a controller cannot process a command it returns an exception response and
sets the high bit (0x80) of the command.
0x01 illegal command
0x02 illegal data address
0x03 illegal data value
Packet returned by controller: | nn | nn | nn | nn nn |
controller address (one byte)
command + 0x80
exception code (0x01 or 0x02 or 0x03)
CRC low byte
CRC high byte