Enclosures (Cooling And Ventilating) - Parker H Series Installation & Service Instructions Manual

Safety Guidelines for the Application, Installation and Maintenance of Solid State Control

4.2 Enclosures (Cooling and Ventilating)

Suitable enclosures and control of the maximum operating
temperature, both of which are environmental variables,
may be needed to prevent malfunctions of solid state control.
The manufacturer's recommendations should be followed
for the selection of enclosures, ventilation, air filtering (if
required), and ambient temperature.
recommendations may vary from installation to installation,
even within the same facility.
4.3 Special Handling of Electrostatic
Sensitive Devices
Some devises may be damaged by electrostatic charges.
These devices are identified and should be handled in
the special manner specified by the manufacturer.
NOTE: Plastic wrapping material used to ship these
devices may be conductive and should not be used as
insulating material.
4.4 Compatibility of Devices with Applied
Voltages and Frequencies
Prior to energization, users and installers should verify
that the applied voltage and frequency agree with the
rated voltage and frequency specified by the manufacturer.
NOTE: Incorrect voltage or frequency may cause a
malfunction of, or damage to, the control.
4.5 Testing Precautions
When testing solid state control, the procedures and
recommendations set forth by the manufacturer should
be followed.
When applicable, instrumentation and test equipment
should be electrically equivalent to that recommended by
the manufacturer for the test procedure. A low impedance
voltage tester should not be used.
High voltage insulation tests and dielectric tests should
never be used to test solid state devices. If high voltage
insulation of field wiring is required, solid state devices
should be disconnected. Ohmmeters should only be used
when and as recommended by the equipment manufacturer.
Testing equipment should be grounded; if it is not, special
precautions should be taken.
C.4.2 Enclosures (Cooling and Ventilating)
NEMA Standards Publication No. 250-1985, Rev. 2, May
1988, classifies enclosures by type number and specifies
their design test requirements.
Also see section 2.1 and 3.6.1.
These
C.4.3 Special Handling of Electrostatic Sensitive Devices
Many problems due to electrostatic discharge (ESD) occur
due to handling of modules during installation or
maintenance.
In addition to specific guidelines provided by an equipment
supplier, the following general guidelines can help reduce
damage due to ESD.
1. Use a grounding bracelet if possible to minimize charge
build-up on personnel.
2. Handle a module by the edges without touching
components or printed circuit paths.
3. Store modules with ESD sensitive components in the
conductive packaging used for shipping the modules.
Also, use conductive packaging when returning static
sensitive modules for repair.
C.4.5 Testing Precautions
Make-do test devices such as incandescent lamps or
neon lamps should not be used for checking voltages in
solid state systems.
impedance; the low impedance of these devices can
effectively change a voltage level from a logic "1" condition
to a logic "0" condition when attempting to make a
measurement. Unexpected machine motion can result if
an output to a controlled device is energized as a result.
Neon lamps do not respond to voltages typically used in
logic circuits (e.g., 32 volts DC or less). Use of a neon
lamp tester could lead to false conclusions about the
voltage level present in a circuit.
High input impedance meters are required to obtain
accurate voltage measurements in high impedance circuits.
Unless otherwise specified by the manufacturer, a meter
with an input impedance of ten megohms or greater is
recommended for making voltage measurements. The
meter must also have sufficient sensitivity to measure logic
level voltages; some meters do not respond to low voltages.
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Incandescent lamps have low
E116P