Dwyer LCR20 - Manual (Page 6)

LCR20 IOM Page 6 of 20 April, 2003
2-4 Wiring Precautions
Before wiring, verify the label for correct model number and options.
Switch off the power when checking.
Care must be taken to ensure that maximum voltage rating specifi ed
on the label are not exceeded.
It is recommended that power of these units to be protected by fuses
or circuit breakers rated at the minimum value possible.
All units should be installed inside a suitably grounded metal
enclosure to prevent live parts being accessible from human hands
and metal tools.
All wiring must conform to appropriate standards of good practice and
local codes and regulations. Wiring must be suitable for maximum
voltage, current, and temperature rating of the system.
Take care not to over-tighten the terminal screws.
Unused control terminals should not be used as jumper points as
they may be internally connected, causing damage to the unit.
Verify that the ratings of the output devices and the inputs as specifi ed
in Chapter 5 are not exceeded.
Electric power in industrial environments contains a certain amount of
noise in the form of transient voltage and spikes. This electrical noise
can enter and adversely affect the operation of microprocessor-based
controls. For this reason we strongly recommend the use of shielded
thermocouple extension wire which connects the sensor to the unit. This
wire is a twisted-pair construction with foil wrap and drain wire. The drain
wire is to be attached to earth ground at the sensor end only.