Siemens 353 User Manual page 175

UM353-1B
Wire Selection - Stranded wire is recommended for most connections, however, solid wire is typically used for
thermocouple extension wire. Carefully select wire size, conductor material, and insulation. Some selection
considerations are:
•
current and voltage to be carried
•
total length of each wire run
•
whether wire will be bundled or run singly
•
indoor or outdoor installation
•
temperature extremes (Use supply wires suitable for 5°C (10°F) above ambient temperature.)
•
exposure to sunlight
•
vibration
•
types of contaminates
Station Common (COM), Terminal 6:
•
Connect station common to the user's instrument bus common at only one point
•
Station common is electrically isolated from case/safety ground, the green ground screw
•
Terminals 6, 9, 18, 21, 24, 34, 40 and 42 are electrically connected. Use the terminals that allow the best wire
routing and the least stress on components, such as range resistors
Digital Input Commons (DIN#-) – Digital input commons are isolated from the station common and case/safety
ground.
Connector Terminal and Ground Screw Torque Specifications:
•
connector terminals - 5 in. lbs (0.56 N m)
•
green case/safety ground screw - 20 in. lbs (2.26 N m)
Crimp-On (solderless) Connectors - A pin-style crimp-on connector can be used when two or more wires or a
combination of wires and component leads are to be inserted into a connector terminal at the rear of the case. Wires
and leads are crimped in the connector and the connector pin inserted in the
selected connector terminal. The connector can provide a more secure
connection when multiple leads are involved. An example of its use is shown at
right. Several crimp-on connectors are provided in various Siemens 353
installation kits, and they are available from most electrical supply sources.
Wire Routing and Conduit - DC wiring should be separated from AC wiring and away from AC powered
pushbuttons, alarms, annunciators, motors, solenoids, and similar devices. Conduit and raceways are commonly
used for routing panel wiring. Wiring not installed in conduit or raceway should be clamped or supported
approximately every 12 inches (300 mm).
April 2012
Installation
Crimp-On
Signal Input Wire Connector
Range Resistor
7-7