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Sensors are connected in a daisy chain connection.
120Ω resistor is used at the end of the chain which is equal to the resistance of the cable.
A twisted pair cable is used for A(+) and B(-).
"VT335t, VT825t, and VT855t monitoring units" have an internal termination, and by default, it is switched to the ON position. (If it is required, it is possible to switch it OFF)
Up to 32 devices can be used.
Overall cable length is no more than 1000 meters.
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| VT485r | Cables |
---|
Eastron SDM220-MODBUS | |||
---|---|---|---|
| B- | red | +12V |
A+ | blue | A+ | |
GND | white | GND |
Physical description
Example 2: (Not recommended) Daisy chain connection (the main controller is located in the middle of the chain)
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