Instruction manual

5. RKC COMMUNICATION PROTOCOL
IMR01H02-E3
26
Continued from the previous page.
Example: When 3 controllers (MA900: 4 channels) are multidrop-connected
Controller 1 Device address 00 + CH1 - 1 = Address 00
Device address 00 + CH2 - 1 = Address 01
Device address 00 + CH3 - 1 = Address 02
Device address 00 + CH4 - 1 = Address 03
Controller 2 Device address 04 + CH1 - 1 = Address 04
Device address 04 + CH2 - 1 = Address 05
Device address 04 + CH3 - 1 = Address 06
Device address 04 + CH4 - 1 = Address 07
Controller 3 Device address 08 + CH1 - 1 = Address 08
Device address 08 + CH2 - 1 = Address 09
Device address 08 + CH3 - 1 = Address 10
Device address 08 + CH4 - 1 = Address 11
As long as the data link is not initialized by sending or receiving EOT, the selecting address
once sent becomes valid.
(3) Data sent from the host computer
The host computer sends data for the selecting sequence with the following format:
!"
When no memory area number is specified
!"
When the memory area number is specified
For the STX, ETX and BCC, see 5.1 Polling (P. 15).
3.2.
BCCETXIdentifierSTX Data
Device address
of controller
Controller
channel number
Addresses used in
selecting sequence
3.2.1.
BCCETXIdentifier
Memory area
number
STX Data
For example, if Address 10 is
selected CH3 corresponding to
Controller 3 is urged to receive
data.
Set the device address number of the succeeding controller to four or more than four plus the same
number of the previous controller. Otherwise (for example, if set to 00, 01 and 02 between Controllers
1, 2 and 3), the address used for polling is duplicated and as a result no normal communication can be
made.
In case of the MA901:
Set the device address number of the succeeding controller to eight or more than eight plus the
same number of the previous controller.
Controller 1: Device address 00, Controller 2: Device address 08, ..........