Relay to voltage supply?

Question

I have an Omron E5C2 temperature controller (http://www.ia.omron.com/data_pdf/data_sheet/e5c2_ds_csm214.pdf). It has two outputs which are meant to turn on or off the circuit. So how do I incorporate a voltage supply into this so as to provide a voltage to my heating strip?

Answer 1

You need to connect the heater voltage to 4 only. Connect the heater from 5 to the other side of the supply.



These are the parts of the data sheet that are related to your question.



“If the load circuit is a heating control system, be sure to connect the load to terminals 4 and 5. If the load circuit is a cooling control system, be sure to connect the load to terminals 4 and 6.”



“We recommend using an external relay to extend the electrical life of internal relays when driving a large capacity load. This is particularly important when the output relay is switched frequently (e.g., with proportional control).”



“Control output Relay output: SPDT, 3 A at 250 VAC, resistive load (switching capacity: 330 VA)”



The data sheet is not very well written. Terminal 4 is the common point of the internal single pole double throw (SPDT) relay. Terminal 5 is the normally-open contact and terminal 5 is the normally-closed contact.



If the heater requires no more than 3 amps at 250 volts AC, you can connect one side of the power supply to terminal 4 and connect the heater between terminal 5 and the other side of the power supply. If one side of the power supply is a grounded neutral, connect that side to the heater and the hot side to terminal 4.



If the heater needs more than 3 amps at 250 volts AC, you must connect the coil of a higher current and/or voltage rated relay to the controller instead of the heater. Connect a contact from that relay between one side of the power supply and the heater. Even if the heater needs less than 3 amps at 250 volts AC it would be better to use an external relay. “This is particularly important when the output relay is switched frequently (e.g., with proportional control).”



PS

2.25 W is a very small heater. Are you sure it is not 22.5 watts, 225 watts or 2.25 kW?



PS2

I think this confirms that the controller power supply is not internally connected to supply the load:



"If a single power supply is used for the E5C2 and the load, the supply voltage of the power supply may vary greatly when the load is open or closed if the capacity of the power supply is not large enough. Make sure that the capacity of the power supply is large enough so that the supply voltage range will be always from 90% to 110% of the rated supply voltage."

Answer 2

There is a drawing that shows the connections. You supply 120 VAC 60 Hz to pins 7 and 8.



Connect a thermocouple, the E52-THE@ Thermistor (replaceable element) or a platinum resistance thermometer to terminals 1 (positive) and 2 (negative).



for output: If the load circuit is a heating control system, be sure to connect the load to terminals 4 and 5. If the load circuit is a cooling control system, be sure to connect the load to terminals 4 and 6.



They recommend using an external relay to extend the electrical life of internal relays when driving a large capacity load. This is particularly important when the output relay is switched frequently (e.g., with proportional control).



What is the voltage of your heater? If it will operate on 120 VAC, less than 3 amps (360 watts) then you can use the relay contact outputs. If it is more than 3 amps, you need an external relay. If it is a different voltage, you can use the contacts, as long as the current is less than 3 amps.



Seems to me that the internal relay is pretty poor, you should always use an external relay.



.

Answer 3

This is not a thermostat, it is an analyzer that converts temperature inputs into either a digital on-off signal or an analog (varying output) signal.



Assuming that you have connected the appropriate input device, i.e. a thermocouple as specified - you will now have an output signal, thermostatically controlled.



Your output is a relay that can handle maximum 3 A at maximum 300 V.



Your heater circuit needs a control power supply, not over 300 V and have a relay that draws no more than 3 A, controlling the main current of your heater.



This heater control relay most be capable of handling the heater current with a safety margin as called for in your local electrical code.



All of this must be installed with proper fuses or circuit breakers to be safe. Summarizing:



Thermocouple

120 V, 2 A power supply to Omron controller - (Read label to know if it is wired for 120 or 220 V)

Omron temp controller (with built in control contacts)

Heater control relay

Heater power supply

Heater



Suggestion, don't mess with this unless you know what you are doing!