- Emerson Remote Terminal Unit Instruction Manual

2-16 / Installation & Operation CI-ControlWave Express
2.3.4 I/O Wiring
ControlWave Express RTUs are provided with card edge terminal blocks that accommodate
field wiring. Wiring is routed into the enclosure/chassis through a slot in the removable
card edge cover.
2.3.4.1 I/O Wire Connections
ControlWave Express RTUs utilize terminal blocks equipped with compression-type
terminals that accommodate up to #16 AWG wire. A connection is made by inserting the
wire’s bared end (1/4” max) into the clamp beneath the screw and securing the screw. The
wire should be inserted fully so that no bare wires are exposed to cause shorts. If using
standard wire, tin the bare end with solder to prevent flattening and improve conductivity.
Allow some slack in the wires when making terminal connections. The slack makes the
connections more manageable and minimizes mechanical strain on the terminal blocks.
Field I/O Wiring is supported by card edge Terminal Block Connectors as follows:
2.3.4.2 Shielding and Grounding
The use of twisted-pair, shielded and insulated cable for I/O signal wiring will minimize
signal errors caused by electromagnetic interference (EMI), radio frequency interference
(RFI) and transients. When using shielded cable, all shields should only be grounded at one
point in the appropriate system. This is necessary to prevent circulating ground current
loops that can cause signal errors.
Process I/O Board I/O Connections
Non-isolated Analog Input Connection (Section 2.3.4.6)
Non-isolated Analog Output Connection (Section 2.3.4.7)
Dedicated Non-isolated Digital Input Connection (Section 2.3.4.3)
Dedicated Non-isolated Digital Output Connection (Section 2.3.4.4)
Selectable Non-isolated Digital Input/Output Connection (Section 2.3.4.5)
Non-isolated High Speed Counter Input Connector (Section 2.3.4.8)
CPU/System Controller Board I/O Connections
Non-isolated Pulse Input Connection (Section 2.3.4.9)
2.3.4.3 Dedicated Non-isolated Digital Inputs
Process I/O Board Terminal Block connector TB2 provides interface to 4 dedicated non-
isolated Digital Inputs DIs). All Digital Inputs support dry contact inputs that are pulled
internally to 3.3 Vdc when the field input is open. Source current for DI#1 through DI#4 is
switch selectable for 60uA or 2mA from the 3.3V supply (SW1-3 ON = 2mA, OFF = 60uA).
Note: SW1-3 sets all DIs and all HSCs (for DI5, DI6, HSC1 & HSC2 SW1-3 ON = 2.2mA
and SW1-3 OFF = 200uA). 15 millisecond input filtering protects against contact bounce.
2.3.4.3.1 Dedicated Digital Input Configurations
Terminal Block TB2 supports four non-configurable DIs. Each DI provides a 60uA or 2mA
source current from 3.3Vdc. Switch SW1-3 must be set to establish the DI source current for
DI#1 through DI4 (SW1-3 ON = 2mA, OFF = 60uA) as well as DI5 & DI6 (SW1-3 ON =
2.2mA, OFF = 200uA). Field wiring assignments are provided in Figure 2-9.
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