Innovate Motorsports OT-1 - Manual (Page 5)

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Also, the CAN standards include mechanisms for error checking and data flow control. Both
these are areas which are either weak or lacking in several of the other vehicle specific protocols
allowed under OBD-II.
1.3 MTS and the Log Chain Concept
As noted above, MTS stands for Modular Tuning System. It was originally developed by Innovate
as a way to mix and match combinations of our data acquisition products and still have a single
connection for computer based logging and analysis.
Products are, literally, electrically chained together. The Serial OUT connection of each device is
fed to the Serial IN of the next one in the chain (or a computer if there are no more devices to
add). Here is an example of a simple 6 channel chain:
Because it is the first device in the chain, the Serial IN on the first LC-1 (an MTS lambda (AFR)
measurement module) is terminated with a small plug (named in honor of California’s governor).
Data then flows from the Serial OUT of that device to the Serial IN of the next LC-1, and so on,
down the Log Chain until the data finally reaches a computer for logging. The order of the data
acquisition devices is not important. However, devices which display information from other
devices, like the two dinner plate sized XD-1/XD-16 digital gauges pictured above (diagram may
not be to scale), must be ‘down stream’ of the devices whose data they display. Similarly,
recording devices must be ‘down stream’ of devices whose data is being recorded.
Please note that the OT-1 does not need a terminator plug when it is the first MTS device in a log
chain. In addition to self termination the OT-1 has another significant difference. It can
communicate with a computer either via its Serial OUT connection (like most MTS devices) or via
a built in USB connection. Both the USB and Serial OUT connection can be used at the same
time. For example:
We have replaced the SSI-4 in the previous example with an OT-1. Now the computer can be
connected via USB directly from the OT-1. The computer can ‘see’ and record data from the OT-
1 and both LC-1s. The Serial OUT connector on the OT-1 is still fed to the gauges. This allows
them to be configured to display OT-1 generated channels as well as the readings from the two
LC-1s in the chain.