Precautions for Correct Use of Temperature Controllers

For the precautions for individual products, refer to the Safety Precautions for that product.

Correct Use

Service Life

Use each product within the range of specifications for that product.

When the Temperature Controller is incorporated in a control panel,make sure that the Controller's ambient temperature and not the ambient temperature of the control panel does not exceed the specified temperature range.

The service life of the Temperature Controller and other electronic devices is determined not only by the number of times the relays are switched, but also by the service life of internal electronic components. Component service life is affected by the ambient temperature: the higher the temperature, the shorter the service life,and the lower the temperature, the longer the service life. Therefore,the service life can be extended by lowering the temperature of the Temperature Controller.

Mounting two or more Temperature Controllers side by side, or mounting Temperature Controllers one above another may cause heat to build up inside the Temperature Controllers, which will shorten their service life. If the Temperature Controllers are mounted one above another or side by side, use forced cooling by fans or other means of air ventilation to cool the Temperature Controllers. Be sure not to cool only the terminals. Otherwise, measurement errors may occur.

Ensuring Measurement Accuracy

When extending or connecting the thermocouple lead wires, be sure to use compensating wires that match the thermocouple type.

When extending or connecting the lead wire of the platinum resistance thermometer, be sure to use wires that have low resistance and keep the resistance of the three lead wires the same.

Make sure that the temperature sensor type and the input type of the Temperature Controller are the same.

There are two types of platinum resistance thermometer: Pt and JPt.Correct measurement will not be possible if the input type of the Temperature Controller is incorrect.

Mount the Temperature Controller so that it is horizontally level.If the measurement accuracy is low, check that to see if the input shift has been set correctly.

Waterproofing

Models for which the degree of protection is not specified and models with IP[]0 degree of protection do not have waterproof specifications.

EN/IEC Standards

If the Temperature Controller is to conform to EN/IEC standards, it is recommended to install the following fuse in the power supply terminal section.

Recommended fuse: T2A, 250-VAC, time-lag fuse with low breaking capacity

Operating Precautions

1. It takes up to 5 s for the outputs to turn ON after the power supply is turned ON. Take this time into consideration when the Temperature Controller is incorporated in a sequence circuit.

2. When using the self-tuning function of the E5[]N, E5[]K, or E5[]J,turn ON the Temperature Controller and load (e.g., heater)simultaneously or turn ON the load before the Temperature Controller. If the load is turned ON after the Temperature Controller, correct self-tuning and optimum control will not be possible. When starting operation after the Temperature Controller has warmed up, turn OFF the power supply and then turn it ON again at the same time as turning ON the power supply for the load. (Instead of turning the Temperature Controller OFF and ON again, switching from STOP mode to RUN mode can also be used.)

3. Using the Temperature Controller near radios, televisions, or wireless devices may cause reception interference.

Parameter Displays

The following displays are use to represent the characters for parameter names on the Temperature Controller.

Seven-segment Digital DIsplay

Eleven-segment Digital Display

Precautions for Correct Use of Temperature Sensors

Precautions for Correct Use

Precautions

・ Make sure that the protective tubing material is suitable for the sensing object. Otherwise, the temperature sensor's protective tubing may be corroded by the sensing object, preventing temperature measurement.

・ Do not subject the temperature sensor's protective tubing to excessive vibration, shock, or weight. Platinum resistance thermometers in particular use extremely fine resistance elements.Using these temperature sensors in locations subject to mechanical shock or vibration may result in broken wires.

Lead Wire Extension

Platinum Resistance Thermometers

Use lead wires for extension with the same resistance and same length for each of the three wires. The resistance of the lead wire will affect the indicated temperature when extended. Therefore, use wires with thick cores. (OMRON does not supply lead wires for extension.)

Thermocouples

Always use compensating conductors for thermocouples when extending the lead wires. Using compensating conductors without thermocouple characteristics and general-purpose lead wires for extension will prevent correct temperature measurement. Make sure that the wires are connected using the correct polarity.

Thermistors

Use cables with thick core wires for the lead wires used for extension. The lead wires do not have polarity.

Regardless of the type of temperature sensor used, resistance to noise will be reduced if the leads are extended. Never extend the lead any further than necessary.

Correct Use

・ Select a location for installing the temperature sensor in which the temperature distribution of the sensing object will not change.

・ Make sure that the length of the temperature sensor's protective tubing is sufficient to touch or insert into the sensing object. The length of metallic protective tubing must be at least 20 times its diameter, and the length of non-metallic protective tubing must be at least 15 times its diameter.

・ Do not repeatedly bend the temperature sensor at the same point.The minimum allowable bending radius of sheathed temperature sensors is approximately five times the protective tubing diameter.Bending part of the sensor at an acute angle and then extending again may result in broken internal wires or cracks in the element.Do not bend the soldered sections.

・ Do not bend the protective tubing while measuring low temperatures, which will cause the protective tubing to become fragile.

・ Do not bend sheathed temperature sensors to within 100 mm of the end to protect the sensing section.

・ Do not allow the temperature of the section connecting the protective tubing and lead wire to exceed 70°C for exposed-lead models or 100°C for heat-resistive models.

・ Do not allow the temperature of the terminal box to exceed 100°C for exposed-terminal models or 80°C for enclosed-terminal models.

・ Do not subject the ceramic protective tubing of high-temperature thermocouples to sudden heating or cooling. Ceramic protective tubing has a low resistance to thermal shock. Either preheat the protective tubing or gradually heat to the required temperature.

・ Do not use standard lead wires in locations subject to strong bending stress or on moving parts. Consider using the temperature sensors designed for moving parts.

Mounting

1. Install explosion-proof models according to the applicable laws and regulations regarding explosion proofing.

2. Sheathed temperature sensors with long protective tubing are coiled for shipping. Straighten the tubing by unwinding it in the opposite direction, without twisting it.

3. Do not excessively bend the section connecting the protective tubing to the lead wires of exposed-lead wires models. Do not insert this section into the sensing object.

4. Do not pull the lead wires with force. Doing so may cause broken wires at the connected section.

5. When measuring at high temperatures that cause the protective tubing to warp, either insert the temperature sensor vertically or use an appropriate means to hold the temperature sensor in place.

6. To obtain more accurate values, maintain the temperature of the exposed protective tubing to prevent heat loss through heat dissipation.

7. If inductive noise is generated in the temperature sensor due to power lines or other source, either change the installation position of the temperature sensor and lead wires or provide a shield for the lead wires.

8. Use airtight temperature sensors for applications using sensing objects below room temperature, to prevent condensation within the protective tubing and faulty insulation.

9. Do not use the temperature sensor in locations that may expose the terminals to water or other liquid.

10.Temperature sensors are precision devices. Do not subject the temperature sensors to shock. Take particular care with products that have ceramic components (ceramic protective tubing,platinum resistance thermometers).

11.Do not use ultrasonic cleaning or otherwise subject platinum resistance thermometers to extreme vibration. Doing so may cause wires to break within a short time. For such environments,consider using sheathed thermocouples, which have a superior vibration-resistant construction compared with platinum resistance thermometers and may be more suitable for the required application, depending on the level of vibration.

12.The life of the protective tubing will be significantly shortened when measuring the temperature of dissolved metals. Select protective tubing material to suit the type of dissolved metal to be measured.

13.Use the following installation methods for applications measuring the temperature of fluids.

(a) Install the temperature sensor vertically to the flow in tubes with relatively large diameters that enable deep insertion.

(b) Install the temperature sensor on a diagonal against the flow in tubes with slim diameters that do not enable deep insertion.

(c) Install the temperature sensor into the convex section of a bend if the tubing diameter is even thinner than in (b).

Use an installation design that provides sufficient strength margin.