Tempco tec-220, Instruction Manual, Page: 12 / 36

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2–4 Power Wiring
The controller is designed to operate at 11–26VAC/VDC
or 90–250VAC. Check that the input voltage corresponds
to the power rating indicated on the product label before
connecting power to the controller.
2–5 Sensor Installation Guidelines
Proper sensor installation can eliminate many problems in a con-
trol system. The probe should be placed so that it can detect any
temperature change with minimal thermal lag. In a process that
requires fairly constant heat output, the probe should be placed
close to the heater. In a process where the heat demand is variable,
the probe should be close to the work area. Some experimentation
with probe location is often required to find the optimum position.
In a liquid process, the addition of a stirrer will help to eliminate
thermal lag. Since the thermocouple is basically a point measur-
ing device, placing more than one thermocouple in parallel can
provide an average temperature readout and produce better
results in most air heated processes. Proper sensor type is also a
very important factor in obtaining precise measurements. The
sensor must have the correct temperature range to meet the
process requirements. In special processes, the sensor might have
requirements such as leak-proof, anti-vibration, antiseptic, etc.
Standard sensor limits of error are ±4°F (±2°C) or 0.75% of the
sensed temperature (half that for special) plus drift caused by
improper protection or an over-temperature occurrence. This
error is far greater than controller error and cannot be corrected
on the sensor except by proper selection and replacement.
2–6 Sensor Input Wiring
2–7 Control Output Wiring
This equipment is designed for installation in an
enclosure which provides adequate protection against
electric shock. Metal enclosures must be connected to
earth ground.
Local requirements regarding electrical installation should be
rigidly observed. Consideration should be given to prevent
unauthorized personnel from accessing the power terminals.
Wiring,
continued…