Innovate Motorsports SSI-4 - Manual (Page 5)

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The Innovate Log-Chain concept
LogWorks 2.0 has the capability to log, display and analyze up to 32 engine parameters. Most
users will use less though. Each of the MTS components reads between 1 and 6 engine
parameters. To interface a multitude of MTS components to LogWorks with a single connection,
the Innovate LogChain concept was introduced.
The SSI-4 can be used as a MTS component in a Log-Chain.
Each of the MTS components has two serial ports (except the LM-1, which has only one). One
serial port is designated as IN-port, the other as OUT port. The OUT-port of one device is
connected to the IN-port of the next device and so on. This way devices can be ‘daisy-chained’ to
build a log-chain for up to 32 channels total. The OUT-port of the last device is connected to the
computer for logging or downloading of logged data.
The device that’s first in the chain is special. It determines the logging sample rate. The first
device in the chain sends a data packet containing its channel data (a sample) to the next device
(downstream, left to right in the diagram) every 81.92 milliseconds. The next device appends its
data to that packet and hands that packet to the next device downstream and so on. At each
device the packet grows in length. The devices in the chain synchronize their sampling of the
engine parameters to the packets, so that all the channels in a packet together represent the
same instance in time. At the downstream end of the log chain (OUT-port of the last device) a
computer or external logger can be connected to store or display the stream data. The XD-1
display is such a device.
This also means that the complete channel data set is ONLY available at the end of the
log-chain. A datalogger capable of recording the log-chain data-stream therefore MUST be
placed at the end of the log-chain. This includes lap-top computers or other loggers.
Commands for individual devices are sent ‘upstream’. A device (incl. a computer or an XD-1) can
send commands to the devices upstream of itself, but not downstream. Commands can include
start-stop recording, calibration/configuration commands and so on. Only the device directly
upstream of the command originator of course will receive the command. This device then
decides, depending on the command, whether to execute the command and whether to pass it
on. An example of a case where the command is executed but not passed on is the start-stop
record command. The first upstream device capable of logging internally will execute the
command, but not pass it on.
As said before, the first device is special because it is the synchronization source for the entire
chain. By plugging its IN-port with the supplied terminator connector, a device can detect that
requirement when it powers up. The terminator connector just connects the transmit and receive
line of the IN-port together. Each device sends a special command out on it’s IN port when it
powers up. This command is ignored and not passed on by any device if received on it’s OUT
port. If the sending device immediately receives that command on its IN-port again, because the
terminator is plugged in, it assumes it is the first and special device in the chain. The LM-1,
having only one serial port, is ALWAYS a special device and MUST be connected to the
beginning of the chain.
The following are some examples of Log-Chains using the SSI-4 and other MTS devices.
NOTE: The SSI-4 does NOT need a terminator plug on it’s IN port. It
automatically detects if another device is plugged into it’s IN port and
terminates the IN port if nothing is plugged in.