Lighthouse Worldwide Solutions ApexR5

Communications
248083447-1 Rev 1 4-5
RS-485 Communications
RS-485 must be used if the instrument is more than 50 feet from a
computer or is installed in an industrial network. Refer to Table 4-5 for
specifics about RS-485. Contact Lighthouse Technical Support for
more information.
Table 4-5 shows the Electronics Industry Association (EIA) industry
standards RS485 specifications.
Table 4-5 EIA Industry Standards for RS-485 Communications
SPECIFICATIONS RS-485
Mode of Operation Differential
Total Number of Drivers and Receivers on
One Line (One driver active at a time for
RS-485 networks)
32 Drivers
32 Receivers
Maximum Cable Length 4000 ft (1,219.2 m)
Maximum Data Rate (40 ft - 4000 ft for
RS422/RS-485)
100Kbs - 10Mbs
Maximum Driver Output Voltage -7V to +12V
Driver Output Signal Level (Loaded
Min.): LOADED
+/-1.5V
Driver Output Signal Level (Loaded
Max.): UNLOADED
+/-6V
Driver Load Impedance (Ohms) 54
Max Driver Current in High Z State
(POWER ON)
+/-100μA
Max Driver Current in High Z State
(POWER OFF)
+/-100μA
Receiver Input Voltage Range -7V to +12V
Receiver Input Sensitivity +/-200mV
Receiver Input Resistance (Ohms), (1
Standard Load for RS-485)
>
12k