I-Gard DSP-OHMNI, Руководство пользователя

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4. WIRING
N o. 14 or No. 16 switchboard wire is used for all current sensor, control and DDR2 connections, which need not be
shielded. 4-wire shielded cable should be used for the serial communications. A typical wiring schematic is shown in
Figure 1a. It is recommended to use twisted pair for wiring from the secondary of the zero sequence current sensors
(TxA) to the DSP-DFM.
Sensor wiring is not generally limited by length and may be up to a kilometer without degradation of performance,
since the sensor is a current source. Sensor wiring should be run in separate conduit from power wiring. The recom-
mended sensor wiring connections are shown in Figure 2, two twisted wires should be run from each sensor X1 and
X2 as indicated to prevent cross coupling between modules. If existing wiring does not allow this connection because
of common connection at X2 as has been common in some installations, then the G terminals of the DSP-DFM mod-
ules should be connected as shown in Figure 3.
Ribbon cables are available in different lengths as shown in Table 4. For other lengths contact I-Gard. The RC-cables
are used for module-to-module connections and are short in length. Note the orientation of the plug as marked on the
DSP-DM display module. If a second row of modules is installed on another DIN rail, the last module on the right can
be connected to the last module on the right on the second row using the RC-30 cable. Either slot can be used on the
DSP-DFM feeder modules for connection.
Figure 1a: Typical One-Line Installation - Unit Substation