4.2 TMS (TOYOTA MONITORING SYSTEM)
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4.2.2
Network Connection Concept
For networking in a plant, connect the network boards (optional) in respective loom control panels
using switching hubs.
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Key Points for Wiring Design
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Maximum number of looms to be connected to a network should be about 200 units. If more than
200 units need to be connected, separate the network using a router. (One network: Max. 200
units including other connecting devices than the looms.)
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Use a switching hub to connect each loom (network board) in the form of star connection.
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Determine the switching hub location so as to limit each network cable length within100 m.
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Do not increase the number of switching hubs at will by taking possible communication delay into
consideration. (Design cascading with 10 stages as the upper limit.)
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Determine the switching hub ports in consideration of the number of looms, their layout, etc.
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For noise prevention in the plant, pass the network cables in dedicated metal conduits. If metal
conduits cannot be laid, use network cables with shielding wires. Provide a distance of at least
300 mm from the power line, and ground the shielding wire on the side of the switching hub.
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When connecting looms to the customer’s intracompany network, always use a router to sepa-
rate the looms from customer's intracompany network.
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Terminology
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Switching hub
A concentrator for accommodating network cables with a switching function.
The switching function refers to a function for reading the MAC address for the destination termi-
nal in the data frame and sending the data only to the port where the destination terminal is con-
nected.
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MAC address
Hardware address to be set up for identifying the device to be connected in the network.
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100BASE-TX, 10 BASE-T
LAN transmission line specifications standardized by 802.3 Sub-committee of IEEE (Institute of
Electric and Electronics Engineers).
