Lighthouse Worldwide Solutions ApexR02p, Operator'S Manual

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ApexRp Operators Manual
248083480-1 Rev 3 34
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.
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)
100 Kbs – 10 Mbs
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 Lad for RS-485)
>12k
Table 4-5 EIA Industry Standards for RS-485 Communications