Motion Coordinator Technical Reference Manual
Fibre-Optic Network 11-13
Network Specification
Network Buffers
The transmit and receive on all nodes is buffered. As far as the user is concerned
the buffers in the membrane keypad do not exist as all the necessary housekeep-
ing is performed by the keypad itself. The only concern to the user is the receive
buffer on the Motion Coordinator. This is 256 bytes long and is used to store the
message characters only. The header and end of message bytes are stripped off
as they are received so it is not necessary to do this through the Trio BASIC pro-
gram.
Network Status
The NETSTAT common parameter shows any errors that have occurred on the net-
work since the last time this parameter was cleared. The errors are displayed as
follows:
2
Direct variable transfer. The value of the variable specified is modified directly,
without needing to be processed by the user program. Message length is 2 bytes
(14 bits) for the variable number and 10 bytes (32 bit integer + 32 bit fraction)
for the variable value. Ignored by membrane keypads.
3
Keypad offset. Message is 1 byte long and tells the keypad the number of nodes
along the ring to send key presses.
4
Keypad Mode
Message is 1 byte long and controls the response of the keypad to key presses.
0 = Character sent on Key ON only
127 = Key ON/Key OFF each send seperate characters
Bit Value Error Type Description
0
1 TX Timeout Shows that a problem has occurred while trying to
put information into the transmit buffer.
1
2 TX Buffer Error indicates an error on transmission from the buffer.
This part of the operation is invisible to the user
and if this error ever occurs please contact TRIO
for further advice.
2
4 RX CRC Error the received variable has become corrupt. The
error flag is set but the variable isn't.
3
8 RX Frame Error an incomplete or corrupt message has been
received.
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