Installation; Installation Considerations; Environmental Considerations - Siemens 353 User Manual

UM353-1B

7.0 INSTALLATION

This section describes installation of a Siemens 353 Process Automation Controller. Topics include: installation
considerations and mechanical and electrical installation.
The installation must conform to the National Electrical Code and all other
applicable construction and electrical codes.
Section 1.4.4 has lists of the items in a typical controller shipment. If the Display
Assembly or a circuit board(s) must be installed in the case, go to Section 10.5
Assembly Replacement for installation information.
Refer to Section 13.9 Agency Approvals as necessary. CSA Hazardous Location
Precautions and Special Conditions for Safe Use are included in this section. Use of
the equipment in a manner not specified by the manufacturer may impair the
protection provided by the equipment.
A warning label, shown at right, is included with the controller. Install the label in a
highly visible location near the rear terminals of the controller to insure that all
plant personnel with access to controller terminals are aware of a potential
electrical shock hazard and, if installation is in a hazardous area, possible explosion
hazard.

7.1 INSTALLATION CONSIDERATIONS

A Siemens 353 is intended for flush panel mounting in a vibration free instrument panel or rack in an indoor or
sheltered location. Mount a single controller in a single-station panel cutout or mount several controllers in a row in
a multiple-station panel cutout. For a watertight panel, mount each controller in a single-station cutout.
The controller can be mounted in a user-supplied enclosure located out-of-doors or in a location whose
environmental parameters exceed controller operating specifications. A thin bead of silicon sealant is often applied
between the controller's Display Assembly and the mounting panel to prevent air or liquid leakage at this joint.
Do not mount the controller where direct sunlight can strike the faceplate or case. Direct sunlight can make the
displays difficult to read and will interfere with heat dissipation.
Mount the controller either horizontally or with a backward tilt (i.e. the front of the case higher than the rear). If the
controller is to be mounted with some electronic recorders or with pneumatic recorders or stations, tilt back
restrictions for these units may have a bearing on panel design and layout.
Route electrical power to the controller through a clearly labeled circuit breaker, fuse, or on-off switch that is
located near the controller and is accessible by the operator. The breaker or switch should be located in a non-
explosive atmosphere unless suitable for use in an explosive atmosphere.
Thermocouple inputs are accommodated with an optional I/O Expander board and a Reference Junction temperature
sensor. At the factory, two Reference Junctions are included in a Range Resistor and Reference Installation Kit.
For troubleshooting and assembly replacement, see Section 10 Maintenance. Refer to this material when installing
or storing a controller or an MPU Controller board.

7.2 ENVIRONMENTAL CONSIDERATIONS

Operate a controller within its environmental specifications to help ensure reliable, trouble-free operation with
minimum down time. Refer to Section 13 Model Designation and Specifications for controller operating
temperatures limits, operating humidity, and maximum moisture content.
April 2012
IMPORTANT
Installation
7-1