Omron C500 PLC Installation and Maintenance Guide

If the ambient temperature inside the control cabinet may exceed 55 ℃, a cooling fan must be installed to ensure that the air inlet and outlet are unobstructed.

Avoid installing the PLC directly above heating equipment (such as high-power transformers), and the distance should be greater than 150mm.

Anti static:

In environments with low humidity, the human body may carry static electricity. Before touching the PLC, first touch a grounded metal object (such as a plumbing pipe) to release static electricity.

During installation, prevent conductive foreign objects such as metal shavings and wire ends from falling into the interior of the casing.

Power selection and current consumption calculation

This is the most error prone step in C500 installation. The power unit of each rack (CPU rack and each expansion rack) must be able to provide sufficient 5V current to all units on the same rack.

4.1 5V current consumption of commonly used I/O units (excerpt)

Input unit:

Model type, point count, 5V consumption (mA)

3G2A5-ID112 DC 5-12V 16 10

3G2A5-ID213 DC 12-24V 16 20

3G2A5-ID215 DC 12-24V slow speed 32 160

3G2A5-ID218 DC 12-24V Fast 32 160

3G2A5-ID212 DC 24V Dynamic 64 300

3G2A5-ID219 DC 24V Static 64 700

3G2A5-IA121 AC 100-120V 16 10

3G2A5-IA222 AC 200-240V 16 12

3G2A5-IM211 AC/DC 12-24V 16 10

Output unit:

Model type, point count, 5V consumption (mA)

3G2A5-OC221 Relay 16 100

3G2A5-OC223 relay independent common terminal 16 100

3G2A5-OC224 relay 32 200

3G2A5-OD411 transistor 1A 16 160

3G2A5-OD412 transistor 0.3A 32 230

C500-OD212 transistor PNP 32 230

3G2A5-OD213 transistor dynamic 64 460 (+5mA x ON point)

3G2A5-OA121 bidirectional thyristor 16 300

3G2A5-OA222 bidirectional thyristor 16 300

C500-OA226 bidirectional thyristor 16 450

Special Unit (Example):

Model Description 5V Consumption (mA)

3G2A5-AD001~005 A/D 2-channel 300

3G2A5-AD006/007 A/D 4-channel 750

C500-AD101 A/D 8-channel 880

3G2A5-DA001~005 D/A 2-channel 550

3G2A5-CT001/012 high-speed counter 330/550

3G2A5-PID01-E PID 1400

3G2A5-NC103-E Position Control 1 Axis 1400

C500-LK009-V1 PC Link 900

C500-SNT31-V4 SYSMAC NET Link 1400

Calculation example:

A CPU rack is equipped with a PS221-E power supply (capable of 5V and 5A current). Installation on the rack: CPU unit (approximately 2A), I/O control unit (approximately 0.3A), one ID218 (0.16A), one OD411 (0.16A), one OA222 (0.3A), one ID212 (0.3A), and one high-precision CT012 (0.55A). Sum=2.77A, less than 5A, feasible.

Note: The PS222-E of the expansion rack has a usable current of 6.5A, which is higher than the power supply of the CPU rack.

I/O Unit Wiring Specification

5.1 Terminals and crimping terminals

The C500 I/O unit uses M3.5 screw terminals, and it is recommended to use crimp terminals. It is forbidden to directly screw bare wires under the screw. The dimensions of the crimping terminals are as follows:

Applicable wire: AWG22-14 (0.3~2.0mm ²)

Screw tightening torque: 8 kg · cm (approximately 0.78 N · m), maximum not exceeding this value

Important: Each unit is equipped with a detachable terminal block. Loosen the installation screws on both sides of the terminal block to remove the entire terminal block. This is very convenient for unit replacement or maintenance, without the need to disconnect the wires.

5.2 Precautions for wiring input units

DC input: Pay attention to polarity. For world standard input units, the COM terminal can be connected to positive or negative, corresponding to Sink or Source inputs.

AC input: If using a reed switch as the input contact, it is necessary to ensure that the rated current of the contact is ≥ 1A, otherwise surge current may cause contact welding.

Two wire sensors (such as photoelectric switches and proximity switches): there is leakage current. If the leakage current is greater than 1.3mA, it may be mistakenly connected when the input is in the OFF state. Solution: Connect a bleeder resistor in parallel at the input end. Calculation formula:

Maximum resistance value R [k Ω]=7.2/(2.4 × I2 leak [mA] -3)

Minimum power W=2.3/R

Input signal pulse width: The response time of the DC input unit is usually 1.5ms (15ms for slow type). If the input pulse width is less than the scanning period, the signal may be lost. It should be solved through programming or adjusting the input filtering time.

5.3 Precautions for output unit wiring

Relay output (OC221/223/224):

Maximum switch capacity: 2A at 250V AC or 24V DC (resistive load)

Inductive loads (such as contactors and solenoid valves) generate reverse electromotive force, and surge absorbers (AC circuit: RC absorption) must be connected in parallel at both ends of the load; DC circuit: freewheeling diode)

Relay lifespan: 300000 cycles under resistive load and 100000 cycles under inductive load; Mechanical lifespan of 50 million cycles

Every 8 output points share the same common terminal, and the total current must not exceed the allowable value of the common terminal (8A)

Transistor output (OD series):

Switching voltage: 12~48V DC

Residual voltage: approximately 1.4-1.5V (TTL output is 0.4V)

Leakage current: ≤ 0.1mA

Response time: 0.2ms (ON), 0.3ms (OFF)

When driving inductive loads, a freewheeling diode must be added