C&S Controls Laser LT RD-1550, Техническое руководство

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10 LaserLight LT 1550 Technical Manual
Communications Cable Distance Limitations
The maximum cable lengths that can be used for various communications types depend on a number of factors.
These include: output impedance of the transmitter, electrical noise in the environment; cable capacitance, gauge,
termination, and shielding.
Given that these and other factors will affect the maximum usable cable length, the following distances can be used
as a general guide for the
Laser LT communications cabling.
Table 2-4. Communications Cable Distance Limitation Chart
RS-232 50 ft (15 m) @ 19,200 baud rate
RS-422 1000 ft (300 m) Twisted pair cable
Fiber Optic 375 ft (114 m)
USB 16.5 ft (5 m)
802.11 330 ft (100 m)
20 mA Current Loop
The 20 mA current loop communication is provided on connector J2 (Port 1) of the CPU board (Figure 2-7,
Table 2-3). Select active or passive switch settings with S1 (receive) and S2 (transmit).
The 20 mA switches enable active or passive selection of the 20 mA current loop communication. Refer to
Figure 2-7 for the switch location on the CPU board.
RS-232
RS-232 connections are provided on connectors J3 and J4 of the CPU board (Figure 2-7).
2 0 m A S e ria l C o m m u n i c a t i o n A c t i v e /
Passive Slide Switches Commport Jumper for Comm
Remote display Heartbeat
(also shown in Fig. 2-7)
In system programming jumpers
(described in Section 6.0)
Port LEDs
Figure 2-7. Jumper Pin Locations
2.3.5 Reset Switch
The reset switch enables a simulated power up reset. It then goes back to normal operation mode. The reset switch
eliminates having to unplug the unit to do a reset. Refer to Figure 2-7 for the reset switch location on the CPU
board.