Connection Of Lattice Slave Heads (Lsh) - Centsys Lattice Installation Manual

Connection of Lattice Slave Heads (LSH's)
When connecting the L1000 to a series of LSH's it is critical to make sure that the RS485 network cables
are correctly wired and terminated.
Any RS485 Network needs the following:
There must be termination matching resistors of 100 Ohms at each end of the cable.
The cable should be twisted. Screened, CAT 5 cable is recommended
The total length of the cable must not exceed 1000 meters
100
Ohm
Fig 10 Twisted Cable
The L1000 and the RSH have 100 ohm resistors built into them and thus all that has to be done is to
decide which two devices happen to be at the end of the line and those resistors are then switched into
circuit. It is critical that ONLY the end two units have the end-of-line (EOL) resistors switched into circuit.
LSH 1
EOL
unit
L1000 can be mounted at any convenient position in the daisy chain.
Fig 11 Sketch showing daisy chaining of connected units
Maximum Overall Length - 1000 metres
Maximum Length of 1000 metres
LSH 2
Units must be daisy chained as shown
L1000 LSH 30
Page 17
100
Ohm
LSH 31
EOL
unit