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Electrical installation 31
Switching on the bus termination
To avoid signal reflection, add 120-ohm termination to the last devices at each end of the
bus line.
You can use the internal resistor of RS-485/EIA-485 adapters or an external passive
termination resistor. The internal termination switch activates also the pull-up and pull-
down resistors.
EIA-485 device
EIA-485 device
EIA-485 device
Termination
activated
Termination
activated
Termination
deactivated
Termination
deactivated
EIA-485 device
Term.
Term.
Term.
Term.
ON
OFF
OFF
ON
J2
J2
J2
J2
Summary of Contents for NETA-21
Page 2: ......
Page 4: ......
Page 18: ...18 Introduction to the manual ...
Page 32: ...32 Electrical installation ...
Page 42: ...42 Start up ...
Page 50: ...50 Program features ...
Page 56: ...56 Front page ...
Page 68: ...68 Users ...
Page 114: ...114 Networks ...
Page 150: ...150 Reporting ...
Page 172: ...172 Security ...
Page 176: ...176 Memory card ...
Page 184: ...184 Frequently asked questions ...
Page 190: ...190 Diagnostics and troubleshooting ...
Page 194: ...194 Technical data ...