The Emerson AXIMA 2000 is a two-axis motion controller. The manuals for it date from 1997 to 2001, and machines built in that period may still run on one; and when it stops working the whole machine usually stops with it. This guide is for maintenance engineers, plant technicians and purchasing managers in the United States. It explains how to read the AXIMA 2000 status display and LEDs, how to work through the manufacturer's troubleshooting logic, and how to decide whether the fault is inside the controller or in the installation around it.
The information comes from the manufacturer's own documents. These are the installation manual (400266-00), the software reference manual (400262-00), the software user's guide (400263-00), the connectivity reference manual (400265-00), the firmware upgrade manual (400266-01) and the manufacturer's AXIMA 2/4000 Test Procedure. Flexa Systems is an independent supplier and is not affiliated with Emerson, Control Techniques or Nidec. We repair this class of equipment at component level through our servo drive and motion control repair service.
What the AXIMA 2000 is
The AXIMA 2000 and AXIMA 4000 are a family of multi-axis controllers. Units carry Emerson Motion Control or Control Techniques branding, and Control Techniques is now part of Nidec. The installation manual describes the controller as a "fully integrated solution" that combines digital servo control, an operator interface, machine I/O and host communications in one industrial chassis. Its 32-bit floating-point digital signal processor (DSP) runs at 50 MHz.
The AXIMA is a controller, not a drive. It does not power motors. It does three things:
- It sends a ±10 VDC analog command to external servo amplifiers. The documented amplifiers are E Series, MX, LX, Epsilon and EN.
- It reads quadrature encoder feedback from each axis.
- It closes the position loop itself, with full PID control, feedforward and digital filtering.
The command output can be set up as a torque (current) command instead of a speed command. A stepper option adds pulse-and-direction outputs for stepper amplifiers. On the AXIMA 2000 this gives two stepper axes.
Up to four Motion, eight PLC and eleven Auxiliary programs can run at the same time. The AXIMA 2000 uses only the first two coordinate systems. Programs are written in AX-WIN, the Windows-based AXIMA software.
Telling a 2000 from a 4000 on the front panel
Both models have four 25-pin female D-sub connectors on the front, so they look almost the same. The difference is how those connectors are assigned:
- On the AXIMA 4000, all four are axis connections.
- On the AXIMA 2000, connectors 1 and 2 are axes. Connectors 3 and 4 are auxiliary encoder inputs, labeled "Encoder 3 for 2000" and "Encoder 4 for 2000".
- The 9-pin port is "Encoder 1 Output" on the 4000 and "Encoder 3 Output" on the 2000.
The installation manual also notes that some pins are not available on the AXIMA 2000's encoder connections 3 and 4.
The order string
The catalog's How to Order section builds the model number from the "AX" prefix plus these fields:
- Number of axes: 2 or 4.
- Stepper axis (starts on axis 1): 0 = all servo axes; 2 = 2 stepper (AX-2000 only); 4 = 4 stepper (AX-4000 only).
- Communication option: 0 = none; M = Modbus; D = Data Highway Plus.
- Analog input: 0 = none; 1 = 4 channels.
- Digital I/O expansion: 0 = no additional I/O; 1 = 32 in/32 out sinking; 2 = 64 in/64 out sinking; 3 = 32 in/32 out sourcing; 4 = 64 in/64 out sourcing.
Record the full label string when you contact us. It tells us which options are fitted.
AXIMA 2000 specifications at a glance
Where manufacturer documents disagree, the table uses conservative wording or names the source document.
| Item | AXIMA 2000 (per manufacturer documents) |
|---|---|
| AC input | 96–264 VAC single phase, 50/60 Hz (installation manual). Externally fuse each ungrounded line at 2 A slow-blow. Inrush is typically 20 A at 115 VAC and 40 A at 230 VAC for 2 ms. |
| I/O supply | Customer-supplied, usually +24 VDC; functions between 18 and 30 VDC. Protected against reverse polarity: a reversed supply blows the +24 VDC fuse. |
| Standard digital inputs | 16, rated 24 VDC. Wired sink or source in groups of eight. Inputs 13–16 can trigger hardware position capture. |
| Standard digital outputs | 12, sourcing only, 18–30 VDC, 150 mA maximum per output continuously. |
| Relay contacts | One drive enable contact per axis, rated 30 VDC and 0.5 A resistive, interlocked with the watchdog relay. One watchdog contact, rated 30 VDC and 0.5 A. |
| Encoder inputs | One per axis plus two auxiliary. Quadrature, differential receiver (DS26LS32), 8 MHz. 5 VDC encoder supply at 250 mA maximum per axis, protected by a PTC. |
| Command output | ±10 VDC, 16-bit, 5 mA maximum. Feeds a differential amplifier input. |
| Stepper option | 2 axes. Open collector, 0 to 4 MHz, no internal pull-up (installation manual). |
| Serial ports | COM 1: RS-232, auto-baud. COM 2: RS-232/422/485, selected by DIP switch. Optically isolated. 38.4 K maximum per the installation manual. Up to 15 units can be multi-dropped. |
| Factory options | Modbus or Data Highway Plus (not both). Analog input: 12-bit, up to 8 single-ended or 4 differential per the installation manual. Expanded I/O: up to 2 banks of 32 in/32 out. |
| Memory | 128K battery-backed RAM, 128K flash |
| Processor / servo update | 32-bit floating-point DSP at 50 MHz; 50 µs per axis servo update |
| Approvals | UL listed (UL508C); CE marked to the EMC and Low Voltage Directives |
| Environment | 0–40 °C rated; NEMA 12 metal enclosure where contaminants are present |
| Size / weight | 11.70 in overall height; 5 lb (2.3 kg) |
Reading the front panel: status display and LEDs
The top of the front panel holds a single-character LED status display. Its decimal point is labeled "Watchdog Indicator". Below it are:
- 16 input LEDs.
- A row of per-axis LEDs for Drive Enable, Drive Status, CW Limit Sw. and CCW Limit Sw.
- The "24v", "Enable Drives" and "Watchdog Output" LEDs.
- 12 output LEDs.
Why there is no built-in fault-code list
Many technicians look for a fault-code chart for the AXIMA 2000. The manufacturer never published one, because the display is "controlled by the programmer." The machine builder's AX-WIN application decides which letter or number appears and what it means. An "F" on one machine and an "F" on another machine can mean completely different things. If the display shows a letter while the machine is running, you need the machine builder's documentation, or the AX-WIN application itself, to interpret it.
The documents describe only four fixed display behaviors:
- Asterisk (*): shown while an AX-WIN application is downloading.
- Decimal point: lit when the watchdog is on. It is normally on.
- All segments lit, including the decimal point: there is no program in the controller.
- Random character: shown the very first time power is applied to a new controller.
| Indicator | Normal state | What it means when it is wrong |
|---|---|---|
| Status display decimal point | On | Off means the watchdog has tripped. The troubleshooting table lists AC power, line noise, grounding and coil suppression as causes; the test procedure attributes a tripped watchdog to the DSP and says to return the unit for repair. |
| Status display character | Whatever the application defines | All segments lit means no program is loaded. If this returns after a period of operation, it may indicate a failed NVM battery. |
| "24v" LED | On | No DC voltage for the digital I/O. Check the supply, the field wiring and the output fuse. |
| "Enable Drives" LED | On when the Enable Drives input is supplied | If amplifiers will not enable, check the 24 V supply first. New En or Epsilon amplifiers ship in Disabled Mode and need their configuration loaded. |
| "Watchdog Output" LED | On; relay contact closed | Off indicates a failure of the watchdog circuit. |
| Per-axis Drive Status / limit LEDs | Reflect the input states | These inputs take no predefined action in the controller. Only the application program acts on them. |
| Output LED | Follows the output command | LED on but no output: the output fuse sits after the LEDs. Check fuse F103 behind the access panel and the voltage at the terminals. |
| Internal ±12 V and +5 V LEDs (behind the red access panel) | All on | Any LED out means the logic supply has failed. |
Confirm any interpretation of the status display against the machine builder's documentation and the AXIMA manuals.
AXIMA 2000 troubleshooting table: symptom and possible cause
The software reference manual (400262-00) has separate troubleshooting tables for the AXIMA Classic and the AXIMA 2000/4000. It warns readers to make sure they are using the correct one. The table below condenses the 2000/4000 version.
| Symptom | Possible causes (condensed) |
|---|---|
| Watchdog fault and/or status display decimal point are not displayed. | Low or no AC power; noise on the AC line; improper grounding; no noise suppression on coils and relays. |
| No torque on motor shaft or amplifiers not enabled. | Low or no external 24 V; axis enable output not programmed "On"; no AC power to the amplifier; amplifier faulted. |
| Motor has torque but will not move when commanded. | Check the encoder and command (DAC) assignments and for non-zero command limit values. Use the Coordinate System, Axis and Program Diagnostics dialogs to check feed hold, output clamp, open servo loop, kill move, stop move, and running or halted programs. |
| Motor jumps on power up. | Set an Encoder Match instruction or request bit before enabling. With the amplifier disconnected, adjust the amplifier offset and then the DAC offset for zero. |
| Output LEDs do not come on. | Check the output status in Application Diagnostics. Halt all programs and set the output from Program Control to see whether programs are fighting over the output. |
| Output LED is "On" but output is "Off". | Check the 24 VDC LED, fuse F103 behind the access panel, and the terminal voltage. Outputs are sourcing only: measure from the output to 24 VDC common. |
| Input LEDs do not come "On". | Check the 24 VDC LED. Measure from the group common to the input (sink or source wiring). Check the input status in diagnostics. |
| Communications between the AXIMA 2000/4000 and your PC cannot be established. | Verify the cables and the address switch setting. Restart the connection sequence. Try address 0. Slow to 9600 baud, cycling power after each baud change. Try a different port on the PC or on the controller. |
| Input LED is "On" but AXIMA 2000/4000 does not recognize it. | Call your service representative. |
| Motor does not move proper distance. | Check the encoder multiplier and counts-per-unit settings and the amplifier's pulses per revolution. Count encoder edges over one hand-turned revolution. |
| Motor moves in the wrong direction. | Change the axis polarity in the Axis Parameters dialog. |
| Motor runs away on power up. | Check the command and encoder wiring at both ends and for loss of feedback. Execute Encoder Preload or Encoder Match before enabling. Check the command output with no motion commanded. Check the encoder phasing: for CW shaft rotation, the count should rise and the command should go negative. |
| Motor is unstable or overshoots when positioning. | Check the LX or MX amplifier tuning, or the AXIMA tuning. |
Most of these causes are outside the controller: wiring, parameters, amplifier state and tuning. Work through them before assuming the AXIMA has failed. Our article on when to fix or replace a servo drive covers the amplifier side of these symptoms.
Bench checks before you pull the controller
Put the machine in a safe state first. The manufacturer's test procedure says to put the machine into a safe state before testing. That can include removing the AXIMA from the machine altogether. The drive enable contacts are interlocked with the watchdog, but connecting an amplifier while it is enabled can cause unwanted motion. Lock out and verify before working on any connector.
- Logic supply LEDs. Remove the red access panel by gently pushing the cover down and then pulling it out. Inside are LEDs for the ±12 V and +5 V logic supplies, which is separate from your 24 V I/O supply. If any of them is out, the logic supply has failed and the controller needs repair.
- Output fuse. The digital outputs are fused, and the fuse sits electrically after the output LEDs. An output LED can therefore be lit while no current flows at the terminal. The troubleshooting table points to fuse F103 behind the access panel; check it with an ohmmeter. The test procedure lists Littelfuse 451002 or Emerson 212032-02 as the replacement.
- Output loading. Each output is limited to 150 mA continuous, and keeping within that limit is the user's responsibility. Verify each load before replacing a blown fuse, or the new fuse will blow too. Inductive loads require a diode.
- Encoder 5 V supply. Each 5 V encoder supply has a PTC in line. Excess current opens it, and it closes again once it cools. Removing the load for a few seconds resets it. A shorted encoder cable can make an axis appear dead without any internal damage.
- COM 1 auto-baud. COM 1 detects the baud rate from one carriage return after power-up. Each time you change the baud rate, cycle the controller's power.
-
Corrupted flash recovery. Corrupted flash can lock up communications and load a bad program into RAM at power-up. The installation manual gives a recovery procedure:
- Power off.
- Set all four address DIP switches ON (the reserved setting).
- Power on.
- Return the switches to the address in use.
- Download the AX-WIN application.
The factory test procedure also includes a diagnostic test program, input and output checks with jumpers and lamps, and a DAC output check on the axis connectors. These steps carry a real risk of shorting the analog output. We recommend leaving the DAC check to a bench with the controller removed from the machine.
Failures that point inside the controller versus the installation
A short checklist can save a lot of time and shipping. Based on the manufacturer's documents, these symptoms point inside the controller:
- The watchdog decimal point stays off even after AC power, grounding and coil suppression have been confirmed good.
- One of the internal ±12 V or +5 V logic LEDs is out.
- An input LED is on but the controller does not recognize the input. The manual's only remedy is to call service.
- All segments light again after a period of operation, which suggests NVM battery failure. The test procedure says to return the unit for repair. No user battery replacement procedure is documented for the 2000/4000.
- The command output is dead or reads far lower than expected during the DAC check.
- An input fails the diagnostic test program.
These symptoms usually point to the installation:
- No 24 V I/O supply, or a blown output fuse caused by overload or reversed polarity.
- An amplifier that is faulted, disabled, unpowered, or a new En/Epsilon unit still in Disabled Mode.
- Encoder wiring or phasing errors, or a tripped encoder supply PTC.
- Tuning problems in the AXIMA or the amplifier.
- Address DIP switch or baud rate settings that do not match the PC.
A simple general rule applies. If a fault stays put with the field wiring disconnected and a known-good supply connected, it is almost certainly in the controller. If it follows a cable or an amplifier, it is not. For a broader look at component-level failure patterns, see our analysis of what fails inside industrial electronics.
Installation mistakes that damage an AXIMA
The installation manual (400266-00) warns about several conditions that cause real hardware damage. If your controller has failed, check for these before installing a repaired or replacement unit. Otherwise the same fault can destroy the next one.
- Floating AC supply. The 264 VAC limit applies from L1 to PE and from L2 to PE, as well as from L1 to L2. If a floating supply exceeds this for a prolonged period, the protection circuits will fail. Use a ground-referenced supply.
- LX command miswiring. Wiring the AXIMA CMD output to the LX drive's common input can damage the controller's analog output.
- Serial devices without a common ground. Failing to connect device grounds together on COM lines can damage the AXIMA or the other device.
- Overvoltage on the analog input option. More than ±10 VDC between any input terminal and "C" can damage the controller.
- Reversed 24 VDC. Reversing the I/O supply blows the +24 VDC fuse under the front access panel.
- Shared or improper grounds. Ground wires should not be shared with other equipment. PE runs by a short wire to a grounding block. TE ties to PE in the enclosure, but not by a jumper at the AC input connector. The AXIMA logic common must go to the same point as the MX or LX logic common.
- Unsuppressed coils. All inductive coils must be suppressed with diodes or RC networks. Coil noise is also listed as a cause of watchdog trips.
- Poor routing and shielding. Keep AC and motor power away from encoder and serial lines. Terminate encoder and command cable shields at the controller end.
Repair or upgrade?
The current Nidec/Control Techniques site lists "Axima Controllers" under superseded products and names "MC Controllers" as the recommended current product. Nidec describes its legacy products as products that are "no longer in volume production."
Upgrading to a newer controller is not a drop-in swap. You would need to:
- Rewrite the AX-WIN application on a new platform.
- Rework the I/O wiring and axis cabling.
- Re-tune every axis and revalidate the machine.
Repairing the existing AXIMA keeps the machine exactly as built, with the same program, wiring and tuning. For a machine that is otherwise healthy, that is usually the faster route back to production. An upgrade makes more sense when the machine is being rebuilt anyway.
Whichever way you go, protect the program. The machine's AX-WIN application lives in the controller's battery-backed RAM and flash. Before you ship anything:
- Make sure you have a saved copy of the application.
- Write down the address DIP switch setting.
- Note the COM 2 and option configuration.
A repaired or replacement controller may need the program downloaded before the machine will run. Flexa does not extract or recover programs, so the backup must come from your own files or the machine builder. If you would rather source a replacement controller, we can quote one on request, although availability of this superseded product cannot be promised. For the amplifier side of the system, you can also browse our Control Techniques parts and servo drives in stock.
Sending an AXIMA 2000 or 4000 to Flexa for repair
Flexa repairs AXIMA controllers at component level through our PLC and controller repair and motion control repair services. Please include the following with the unit:
- Symptom notes: what the machine was doing when it failed, and whether the fault is constant or intermittent.
- LED states: whether the decimal point was lit, what the status display showed, and the states of the "24v", "Enable Drives", "Watchdog Output" and internal logic LEDs.
- Firmware revision if known. A6 was the initial 2000/4000 release.
- Options fitted: stepper, Modbus or DH+, analog input, expanded I/O. The full model string from the label covers all of these.
- Installation history: any recent wiring changes, power events or amplifier replacements.
Every repaired unit is bench-tested and covered by our 2-year warranty. See the full warranty terms and coverage for details. If a line is down, ask about our rush repair service. You can browse repair case studies or read about another legacy motion product we repair. When you are ready, call (254) 254-0005 or request a repair quote online.
Frequently asked questions
Does the AXIMA 2000 have a built-in list of fault codes?
No. The single-character status display is controlled by the machine builder's AX-WIN program, so any letter or number shown means whatever that program defines. The only fixed behaviors are an asterisk during download, the decimal point as the watchdog indicator, all segments lit when no program is loaded, and a random character on the very first power-up. Check the machine builder's documentation for application codes.
What does it mean when the decimal point on the status display is off?
The decimal point is the watchdog indicator and is normally on. If it is off, the watchdog has tripped. The manufacturer's troubleshooting table lists low or missing AC power, AC line noise, improper grounding and unsuppressed coils as causes. If those are all ruled out, the test procedure attributes the trip to the DSP, which means the controller needs repair.
Why are all segments of the display lit?
All segments plus the decimal point lit means the controller has no program. Download a known-good application, cycle power and check again. If the display returns to all segments after a period of operation, the manufacturer's test procedure says this may indicate a failed NVM battery. In that case the unit should be returned for repair.
Will I need to reload my program after a repair?
Possibly. The AX-WIN application is stored in battery-backed RAM and flash, so a repaired or replacement controller may need the program downloaded again. Keep your own saved copy of the application and record the address DIP switch setting before shipping. Flexa does not extract or recover programs, so the backup must come from your files or from the machine builder.
Can a superseded AXIMA controller still be repaired, and is it covered?
Yes. Nidec lists Axima Controllers as superseded, with MC Controllers as the recommended product, but the AXIMA 2000 and 4000 can still be repaired at component level. Flexa repairs them independently. Each repaired unit is bench-tested and backed by a 2-year warranty. Call (254) 254-0005 or request a quote online to get started.
