Servomex SERVOTOUGH LaserExact 2950, Руководство оператора

Страница: 62 / 72

SERVOTOUGH LaserExact Monitor, Operator Manual 02950001A_1
56 C
HAPTER
6
Junction list Terminal: Color code: Description: Comments:
J2 1 White/Orange
TX+
J2 2 Orange
TX-
J2 3 White/Green
RX+
J2 4 Green
RX-
for straight
through
connection (hub)
Junction list Terminal: Color code: Description: Comments:
J2 1 White/Green TX+
J2 2 Green TX-
J2 3 White/Orange RX+
J2 4 Orange
RX-
for cross over
connection (direct
to PC)
Table 6-4: Cabinet – Ethernet connection
6.5 Current loop (4-20 mA) input connections (PLC)
External pressure and temperature probes to the instrument are wired inside the
cabinet to the terminals for the power cable connection. The probe outputs are
connected to the screw terminals according to Table 6-1 i.e. the probe outputs are
connected to the screw terminals marked with Probe+ and Probe- (or +24V for
passive probe). Probe refers to Temperature, Pressure or Extra (Flow).
Note that conductors with area 0.14-1.5 mm
2
(AWG 26-16) must be used. The
cable outer diameter must be 7 – 12 mm.
Figure 6-2 and Figure 6-3 show how active and passive 4-20 mA current loop
input probes (referred to as PLC) are connected to the instrument. The
Probe+
and Probe- constitute differential inputs which are tolerant to common mode
voltages up to
±
200V. Probe+ and Probe- are connected internally in the
instrument by a 100
Ω
resistor, which give a voltage drop of 2V at 20mA. Several
instruments can therefore be chain connected to the same probe by connecting
Probe- of the first instrument to Probe+ of the next instrument, etc.
Figure 6-2: Current loop input, active probe
100
Instrument
Main unit
(Transmitter)
24V
Probe
Probe
Probes AGND
4-20 mA probe
.
N
C
N
+24V DC, 80mA
AGND
Signal
Signal
External
power