Yaskawa Remote Serial Communication Controller LAN Node PCB for use with Microtrac DSD LAN - Manual (Page 5)

data. These parameters are fixed in the
software and can only be changed by changing
the software version and providing new
EPROMs.
The format of the data is 1 start bit, 8
data bits, no parity bit, and 1 stop bit, for a total
of 10 bit transmission frame.
The speed of the RS-232 serial data is
9,600 baud (bits/second).
RS-232 Serial Port Protocol
All messages passed to and from the
RSC on the RS-232 serial port are in the
following format:
[ SOH | NOT SOH | LENGTH | DRIVE # | MSG
TYPE |
MSG DATA | CHECKSUM
]
The SOH is a single byte field that is the
first part of the start message synchronization
sequence. It is represented by the ASCII SOH
character, value 001H. It, together with the NOT
SOH field, is to be used to synchronize the start
of a message.
The NOT SOH is a single byte field that
is the second, and last, part of the start of
message synchronization sequence. It is
represneted by the logical NOT of the ASCII
SOH character, value 0FEH. It, together with the
SOH field, is to be used to synchronize the start
of a message.
The LENGTH is a single byte field that is
the hexadecimal number of bytes in the
message. The value of length is the sum of the
number of bytes in the DRIVE #, MSG TYPE,
MSG DATA and CHECKSUM fields.
The DRIVE # is a single byte field that is
the hexadecimal number of the drive that is
being communicated with. When the RSC sends
a message to the external device, the DRIVE #
is the source of the message. When the RSC
receives a message from the external device,
the DRIVE # is the destination of the message.
The range of valid DRIVE #'s is from 001H to
063H (1 to 99 decimal).
The MSG TYPE is a single byte field that
is the hexadecimal code whose value defines the
significance and length of the message data.
The MSG DATA is a multi-byte field
whose contents are dependent upon the MSG
TYPE field value.
The CHECKSUM is a single byte field
that is a byte wide checksum of the message, in
hexadecimal format. The checksum is the sum
of all previous characters except the start of
message sychronization characters (SOH and
NOT SOH). It is used to check the vaildity of the
message.
MSG Type Values. The following is a list
of the message type values that are used:
MSG
TYPE MEANING
010H Remote Logic Output
Allocation Request
011H Remote Numeric Output
Allocation Request
012H Remote Logic Input Configure
013H Remote Numeric Input Configure
MSG
TYPE MEANING
020H Display Node Request
021H Display Abort
022H Display Message ASCII Response
023H Display Variable ASCII Response
024H Display Value Response
025H RDU Lockout Command
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