Woodward 2301E-ST, Installation And Operation Manual

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Manual 26694 2301E-ST
Woodward 18
Electrical Connections
Due to the hazardous location listings associated with this product,
proper wire type and wiring practices are critical to operation.
Do not connect any cable grounds to “instrument ground”, “control
ground”, or any non-earth ground system. Make all required
electrical connections based on the wiring diagrams.
All inputs and outputs are made through screwless spring-actuated terminal blocks. For EMI reasons, it is
recommended that all low-current wires be separated from all high-current wire.
The spring clamp can be actuated using a standard 2.5 mm or 3/32 inch flat bladed screwdriver. The
terminal blocks accept wires from 0.08–4 mm² (27–12 AWG). Two 0.8 mm² (18 AWG) or three 0.5 mm²
(20 AWG) wires can be easily installed in each terminal. Wires for the fixed mounted power terminals
should be stripped 5–6 mm (0.22 inch) long.
It is recommended that stranded wire be used for connections to the
terminal block. Do not tin (solder) the wires that terminate at the
terminal blocks. The spring-loaded terminal blocks are designed to
flatten stranded wire and if those strands are tinned together, the
connection loses surface area and is degraded.
Shields and Grounding
An individual shield termination is provided at the terminal block for each of the signals requiring
shielding. All of these inputs should be wired using shielded, twisted-pair wiring. The exposed wire length
beyond the shield should be limited to one 25 mm (1 inch). Relay outputs, contact inputs and power
supply wiring do not normally require shielding, but can be shielded if desired.
The 2301E-ST is designed for shield termination to earth ground at the control. If intervening terminal
blocks are used in routing a signal, the shield should be continued through the terminal block. If shield
grounding is desired at the terminal block, it should be ac coupled to earth. All other shield terminations
except at the control should be ac coupled to earth through a capacitor. A 1000 pF, 500 V capacitor is
sufficient. The intent is to provide a low impedance path to earth for the shield at frequencies of 150 kHz
and up. Multiple direct connections of a shield to earth risk high levels of current to flow within the shield
(exception, see note below on cabinet installations).
Shields can be grounded at both ends (2301E-ST and load) if the cable length is sufficiently short (within
a cabinet) to prevent ground loop current in the shield.
Cabinet Installations: If the 2301E-ST is installed in a cabinet,
shielded I/O can be terminated directly to the cabinet (earth ground)
at the entry/exit of the cabinet, as well as at the control
(recommended).
For EMC reasons, it is recommend that all low-current wires be
separated from all high-current wires. Input Power ground terminal
should also be wired to earth ground.
Released