OMRON NX102 Hardware Installation Guide

OMRON NX102 CPU Unit Hardware Installation and Troubleshooting Manual

The NX102 CPU unit in the Omron NX series machine automation controller is an ideal choice for medium scale motion control and logic control due to its compact 72mm width, built-in EtherCAT master station and dual EtherNet/IP ports, as well as the ability to support up to 32 NX I/O units for expansion. This controller can maintain user programs and hold variables (excluding clock data) without the need for batteries, supports wide temperature operation from -10 to 55 ℃, and has been certified by NK/LR classification society. For on-site engineers, mastering the key points of hardware installation, power system design, fault indicator diagnosis, and regular maintenance can significantly shorten the debugging cycle and reduce unplanned downtime. This article is based on the NX102 hardware user manual (W593) and extracts a complete operation guide from control cabinet layout to battery replacement.

Product Overview and Core Specifications

The NX102 series includes multiple models, with differences in program capacity (5 MB), variable memory (1.5 MB for persistent/32 MB for non persistent), maximum number of control axes (4 to 15 axes), and support for database connections. All models are equipped with:

Built in EtherCAT master station (Class B, compliant with motion control standards, supports linear, daisy chain, branch, and ring topologies)

Dual EtherNet/IP ports (10BASE-T/100BASE-TX, supporting label data links and CIP messages)

NX bus interface, capable of connecting up to 32 NX units (digital I/O, analog, temperature input, position interface, etc.)

SD storage card slot (for backup, recovery, program transfer)

Battery free operation: User programs, set values, and hold variables are stored in non-volatile memory; The clock data is held by a built-in capacitor (approximately 10 days at 40 ℃). If long-term power outage is required to maintain the clock, CJ1W-BAT01 battery can be optionally installed

Main hardware specifications: size 72 × 100 × 90mm, weight 390g, protection level for panel installation (IP20), power supply 24VDC (20.4~28.8V), unit power consumption 5.8W, NX unit power supply capacity 10W, power terminal current capacity 4A.

System configuration and installation steps

2.1 Basic System Composition

A complete NX102 controller system includes:

CPU rack: NX102 CPU unit+NX unit (up to 32)+end cover (NX-END02, provided with CPU)

EtherCAT network: Connect servo drives, encoder input slaves, and EtherCAT slave terminals (such as NX-ECC couplers+NX units) through built-in ports

Upper level connection: Connect Sysmac Studio programming software, HMI or other controllers through EtherNet/IP port

2.2 Installation Preparation

Installation location: Inside the control cabinet, with an ambient temperature of 0-55 ℃, humidity of 10% -95%, no condensation, altitude ≤ 2000m, and pollution level 2.

DIN rail: It is recommended to use OMRON PFP-50N/100N (35mm wide, 7.3mm high) or Phoenix Contact NS 35/7.5 PERF. The guide rail needs to be reliably grounded.

Spacing: Leave at least 20mm of ventilation space at the top and bottom, and space for replacing units on both sides.

Tools: Phillips screwdriver (model XW4Z-00B or SZF 0-0, 4 × 2.5), zip ties, wire cutters, etc.

2.3 Installing CPU Unit and NX Unit

Fix the DIN rail to the backplate (M4 screws, torque 1.2N · m, spacing ≤ 105mm).

Confirm that the DIN rail hook on the back of the CPU unit is in the unlocked position (pulled up).

Press the CPU unit towards the guide rail and lock the hook downwards. Confirm firmness.

Remove the end cap on the right side of the CPU (installed at the factory). Slide the first NX unit along the guide rail so that its upper and lower guide hooks engage with the CPU unit, and press it towards the guide rail until the hook locks. Repeat until all NX units are installed.

Install the end cover to the right side of the last NX unit, slide it in and lock it.

Install end plates (PFP-M) at both ends of the rack to prevent lateral movement of the unit.

Attention: The NX unit connector contains signal pins, do not touch or contaminate them; Do not write or paste labels in the prohibited area of the unit casing (near the connector) to prevent foreign objects from entering the connector and causing poor contact.

Power system design

The power system of NX102 is divided into two channels: Unit Power and I/O Power.

3.1 Unit Power Supply

Powered by an external 24VDC power supply, connected to A1/B1 (24V) and A3/B3 (0V) of the CPU unit terminal block. Two 24V terminals and two 0V terminals are connected in parallel internally and can be used for wiring to subsequent additional power supply units.

The terminal capacity is 4A, and the CPU unit itself consumes 5.8W, while providing up to 10W of NX unit power (via NX bus) to the NX unit.

If the total power consumption of the NX unit exceeds 10W, an additional NX unit power supply unit (NX-PD1000, etc.) must be inserted in the middle, which takes power from the outside and supplies power to all units on the right side. Attention: Adding NX unit power supply unit will cut off the power supply from the left unit (electrical isolation).

3.2 I/O Power Supply

Some NX units (such as digital I/O and analog) require I/O power supply to drive external sensors or loads. I/O power can be provided in the following ways:

Power supply through NX bus: An additional I/O power supply unit (such as NX-PF0630) needs to be inserted on the right side of the CPU, connected to an external 24VDC power supply, which supplies power to all I/O on the right side through the bus. The maximum total current is 10A.

External separate power supply: Some units come with I/O power terminals that can be directly connected to an external power source.

Hybrid power supply: If different groups of NX units require different voltages (such as 24V and 12V), or if a single 10A is insufficient, multiple additional I/O power supply units can be inserted to separate the circuits.

3.3 Power Capacity Calculation

Unit power supply: Total power consumption=CPU power consumption+∑ (internal power consumption of each NX unit). If the total power consumption is ≤ 10W, there is no need to add NX unit power supply. Otherwise, it needs to be divided into multiple segments.

I/O power supply: It is necessary to calculate the sum of I/O current consumption (including input current, output load current, sensor consumption current) of each unit, and consider the bus voltage drop. The voltage drop is related to the total current and the number of units passed through (voltage drop per unit ≈ 0.02V x total current (A)). Ensure that the power supply voltage of the farthest unit still meets its specifications.

Wiring and Grounding

4.1 Terminal block wiring

The CPU unit provides a detachable screw free clamping terminal block (model NX-TBC082, 8-terminal, including functional grounding terminal). Wiring method:

Strip the wire with a length of 8-10mm, use a needle shaped terminal with an insulated tube (Phoenix Contact AI series) or directly use stranded wire/single stranded wire.

For currents above 2A, it is necessary to use tin plated wires or tubular terminals.

Insertion method: Tilt a straight screwdriver 10-15 ° and insert it into the release hole (press to feel the spring rebound), maintain pressure, insert the wire or terminal into the circular terminal hole, and then pull out the screwdriver.

Wire fixing: If the current is greater than 2A and bare stranded wire is used, tie the wire bundle to the binding holes on both sides of the terminal block with zip ties.

4.2 Grounding

The functional grounding terminals (A7/B7) of the CPU unit must be grounded (grounding resistance ≤ 100 Ω). The recommended grounding wire is 2.0mm ² or larger.

DIN rails should also be grounded. If the surface of the guide rail is insulated (such as anodized aluminum), a DIN rail isolation gasket (NX-AUX01) should be used to isolate the guide rail from the backplate, and then grounded separately.

For EtherCAT/EtherNet/IP communication cables, it is recommended to use an equipotential bonding system or star grounding to avoid grounding loops. The shielding layers at both ends need to be connected to the connector housing, and the housing should be well grounded to the rack.

4.3 Power on sequence

To prevent output misoperation, the external circuit should ensure that the unit power supply of the controller is connected before the I/O power supply of the controlled system; When there is a power outage, the opposite is true. The controller takes about 20 seconds to start (depending on the configuration), during which the RUN indicator light flashes at 2-second intervals. At this time, the NX unit output is OFF, but the output behavior of the EtherCAT slave station depends on its parameter settings. System defined variables should be used in the program to confirm the establishment of communication before controlling.

Fault indicator light diagnosis

5.1 CPU unit status indicator light (located on the front)

Meaning of indicator light color and status

POWER green light, normal power supply

No power supply or voltage exceeding the limit

RUN green light, RUN mode running normally

2-second interval flashing startup (entering RUN/PROGRAMME)

2 seconds flashing continuously for ≥ 30 seconds, system initialization error

Extinguish Program mode, reset in progress, or major malfunction

ERROR red light indicates a major fault (control stopped) or CPU abnormality

Partial fault level error with 1-second interval flashing (a certain functional module stops) or minor fault (some functions are limited)

Eliminate normal or monitoring information

BUSY yellow flashing non-volatile memory access in progress

Eliminate idle time

SD PWR green, SD card powered on

Flashing backup/restore/compare operation in progress

SD card not powered or not inserted

SD BUSY yellow flashing SD card access in progress

Eliminate no access

Important: Do not turn off the power when the BUSY indicator light is flashing, otherwise it may cause the user's program or settings to not be saved correctly, and a major malfunction will occur when powered on next time.

5.2 EtherNet/IP Port Indicator Light (NET RUN/NET ERR/L/A)

NET RUN green light: normal startup; Flashing: Ethernet communication is in progress (such as tag data link establishment); Extinguish: Unable to communicate.

NET ERR red light: unrecoverable error; Flashing: Recoverable errors (such as TCP/IP parameter errors, label data link settings errors); Extinguish: No errors.

5.3 EtherCAT Port Indicator Light (NET RUN/NET ERR/L/A)

NET RUN green light: Process data communication is running; Flashing: only message communication or input data operation; Extinguish: Communication has stopped.

NET ERR red light/flashing: recoverable error; Extinguish: No errors.

L/A yellow light: The link has been established; Flashing: transmitting and receiving data; Extinguish: The link has not been established.

If the ERROR light flashes or stays on, you can view detailed error codes and countermeasures through the "Event Log" of Sysmac Studio. Common initial faults include:

Power OFF detection: The power supply voltage briefly drops below 20.4V, but remains within the allowable range (2-8ms). If it occurs frequently, the power capacity needs to be checked.

SD memory card access error: Unplug the card or power off when SD BUSY is on. Solution: Reformat the SD card or replace it.

Unit configuration verification error: The actual installed NX unit does not match the software configuration. Need to synchronize or reconfigure online.

Battery replacement and clock maintenance

The NX102 factory does not have a battery installed. If you need to maintain the clock during long-term power outages (beyond the capacitor retention period), you can choose to purchase CJ1W-BAT01 battery (with a lifespan of 5 years).

Replacement steps:

The controller should be powered on for at least 5 minutes (to charge the capacitor).

Power off (recommended) or ensure that static electricity has been released from the body.

Open the battery cover in the upper left corner of the CPU, unplug the old battery connector, and remove the old battery.

Insert a new battery (note that the production date is within two years), insert the connector into the battery interface, place the battery in the slot, organize the wiring harness, and close the cover.

Power on again, set the 'Battery related Error Detection' to 'Usage' using Sysmac Studio, and adjust the current clock.

Battery error handling:

If the battery is not installed or depleted, the clock data will start running from January 1, 1970, and the ERROR light will flash (if detection is enabled).

If the battery has been installed but reports' low battery voltage ', it indicates that the battery level is low and needs to be replaced as soon as possible. The error will be automatically cleared after replacement.

The battery life will be shortened in high temperature environments (55 ℃), and it is recommended to replace it regularly (such as every two years) as a preventive measure.

Safety circuit and external interlock

The controller itself cannot guarantee the output of a safe state in all faults, and emergency stop, interlock, and limit circuits must be designed in the external circuit. Pay special attention to:

When a major failure occurs in the CPU unit (such as watchdog error), all digital outputs will be forcibly turned off.

But the internal relays or transistors of the output unit may be stuck or short circuited, causing the output to be unable to be disconnected. Therefore, an external contactor is required to form a safety circuit.

For forward and reverse control (such as motors), interlocking contactors (MC1 and MC2) should be used externally to prevent software from mistakenly outputting both directions simultaneously.

When using EtherCAT slave, if communication is interrupted, the output behavior depends on the slave settings (usually set to hold the last value or OFF). Appropriate 'fault softening operations' should be selected based on risk assessment.

Regular maintenance and cleaning

Cleaning: Wipe the surface of the unit with a dry soft cloth every month; If the oil stains are severe, you can use a damp cloth containing 2% neutral detergent to wring out and wipe, then dry with a dry cloth. Do not use diluents, benzene, or chemical cloths.

Periodic inspection (every 6-12 months):

Is the power supply voltage within the range of 24VDC ± 20%.

The ambient temperature is 0-55 ℃, and the humidity is 10% -95% without condensation.

Are there any dust, salt, or corrosive gases present. Use an air gun or vacuum cleaner to clean the control cabinet.

Is the DIN rail hook securely locked and are the end plate screws loose.

Are the cables damaged and the connectors secure.

Battery replacement: Even if there are no errors, it should be replaced before the 5-year lifespan expires.

Common fault cases and quick countermeasures

Case 1: After power on, the RUN indicator light does not light up, but the POWER light lights up

Possible reasons: The CPU is in Program mode, or the boot mode is set to Program, or there is an initialization error.

Troubleshooting: Use Sysmac Studio to connect and view the controller mode. If automatic operation is required, set the startup mode to RUN mode. If the ERROR light flashes, check the event log.

Case 2: ERROR light stays on (red), RUN light goes off

Possible reasons: Major malfunctions such as CPU hardware errors, watchdog timeouts, and fatal user program errors.

Troubleshooting: Power on again after a power outage. If it still stays on, using Sysmac Studio for fault diagnosis may require replacing the CPU unit.

Case 3: Some NX units do not work, but the CPU is normal

Possible reasons: Insufficient power supply to NX unit, or I/O power not provided, or incorrect unit configuration.

Troubleshooting: Calculate if the total power consumption exceeds 10W. Check if the unit is securely plugged into the bus connector. Use Sysmac Studio to check if the unit configuration matches the actual situation, and perform 'synchronization' if necessary.

Case 4: EtherCAT communication abnormality, NET ERR flashing

Possible reasons: duplicate node address from the substation, cable disconnection or length exceeding 100m, topology error.

Troubleshooting: Check the uniqueness of node addresses for all slave stations; Use shielded CAT5e or above twisted pair cables; If using a ring topology, the project unit version 1.40 or above and the cable redundancy function must be enabled.

Case 5: SD card not recognized or backup failed

Possible reasons: incorrect SD card format (requiring FAT32 or FAT16), expiration of card lifespan, incorrect DIP switch settings.

Troubleshooting: Format SD card using Sysmac Studio; Check the DIP switch pin 2 (automatic transmission) and pin 1 (safe mode) settings; Replace the SD card recommended by OMRON.

Quick check of DIP switch function

There are four DIP switches (pins 1-4) at the bottom of the NX102 CPU unit:

Pin function ON/OFF

1. Backup execution is normal

1 and 2 restore pin 1=ON, pin 2=OFF -

1,2,3 automatic transmission pins 1=OFF, 2=OFF, 3=ON -

1, 2, 3, 4 safety mode pins 1=ON, 2=OFF, 3=OFF, 4=OFF -

1, 2, 3, 4 allow connection pins 1=OFF, 2=OFF, 3=ON, 4=ON to Sysmac Studio/NA that do not support secure communication

Safe mode: After power on, it directly enters the Program mode without executing user programs, making it easier to troubleshoot.