What the E1294 alarm means

The 24 V I/O supply on the servo board dipped below its threshold; inputs to the servo logic become unreliable and the controller faults. This is a routine repair in our workshop for Kawasaki E / F / C series (AS language) systems, and we normally pin it down during the first site check.

Most common causes

  • Overloaded or sagging external 24 V supply
  • Loose 24 V wiring at the servo board
  • Short to ground on an I/O line pulling the rail down
  • Failing 24 V power supply unit
Field note: Begin with the first item in the list; it has a far higher on-machine occurrence rate than the others.

Step-by-step field fix

  1. Measure the 24 V rail at the servo board under load
  2. Check for sagging when solenoids/valves actuate
  3. Inspect I/O wiring for shorts to ground
  4. Tighten all 24 V terminals
  5. Replace the 24 V supply if it cannot hold the rail
Safety first: For Kawasaki e1294, this alarm family involves the DC bus, which sits at several hundred volts and stays charged for minutes after power-off - touching terminals is a shock hazard. On site you may not carry out the first step yourself: Measure the 24 V rail at the servo board under load. Beyond that it is the DC bus and power stage work - leave it to a professional. On Kawasaki e1294: checking incoming voltage at the disconnect and looking at breakers and fuses is fine to do yourself; opening the cabinet to touch bus terminals or pulling power modules needs a qualified electrician.

How we diagnose drive alarms on site

Kawasaki e1294 belongs to the drive & power stage family. On Kawasaki e1294 the failing stage is cabinet drive boards (1GA / 1FA class) and power-stage modules per axis on the E-Controller / D-Controller / F-Controller - the fault sits on the energy chain: mains input, rectification, DC bus, braking resistor, inverter power devices and the drive board. We start reading Kawasaki e1294 at the pendant ERROR HISTORY with AS error numbers (D / E / P prefixes).

The chain involved in Kawasaki e1294 runs: three-phase mains -> rectifier -> DC bus (bus capacitors) -> brake chopper / braking resistor -> inverter (IGBT) -> motor.

Bottom line up front: Overloaded or sagging external 24 V supply is the first suspect for Kawasaki e1294, but read it along the energy chain: Any link on this chain dropping voltage shows up at the end as a drive alarm, so order matters. We measure the mains first: more than 3% phase imbalance is enough to sag the bus under load, and plenty of bus over/under-voltage alarms are actually a grid problem wearing a robot costume. Mains fine, then the bus capacitors - bulged cases, weeping electrolyte or a lifted vent mean replacement; capacitance down 20% or more cannot hold the bus during braking. Last, the braking resistor: healthy values sit in the tens of ohms depending on rating, and an open or drifted resistor trips regenerative overvoltage directly.

Field notes on this page cover Kawasaki e1294 (Servo Board IO 24V Dropped); written by the Henghuan repair team, updated 2026-10-01.

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Related Drive & Power Stage alarms

E1028 — Motor Overload (Axis XX) D1028 — Servo Board DC Power Abnormal (Servo FPGA) D1562 — Power Sequence Board — AC External Voltage Too High
Same family: this code belongs to the Drive & power stage alarms family - the page collects all Drive & power stage-family codes we have handled, with the common inspection order and spares.
Other brands: we also keep field-fix libraries for Staubli · Epson · Nachi and more — see the complete alarm code hub.

Frequently asked questions

QWhat does the Kawasaki e1294 alarm mean?

The 24 V I/O supply on the servo board dipped below its threshold; inputs to the servo logic become unreliable and the controller faults. This is a routine repair in our workshop for Kawasaki E / F / C series (AS language) systems, and we normally pin it down during the first site check. Kawasaki e1294 sits in the drive & power stage family; on our work orders the highest-frequency trigger for this code is "Overloaded or sagging external 24 V supply".

QCan I clear a Kawasaki e1294 alarm myself?

Whether Kawasaki e1294 clears on its own depends on the outcome of "Measure the 24 V rail at the servo board under load". Finish the flow with "Replace the 24 V supply if it cannot hold the rail" to confirm Kawasaki e1294 - do not skip it. If that step is clean, the second most frequent cause on Kawasaki e1294 is "Loose 24 V wiring at the servo board". After clearing Kawasaki e1294, watch it for one shift. A second trip means stop and let an engineer arrive with the right test gear for the DC bus and power stage.

QFor drive/power alarms like Kawasaki e1294, what spares do you bring on site?

The commonest causes we see on Kawasaki e1294 are "Overloaded or sagging external 24 V supply, Loose 24 V wiring at the servo board, Short to ground on an I/O line pulling the rail down", so we stock the van against those. For Kawasaki e1294 specifically, we stock the van along the energy chain: braking resistors, bus capacitors, input fuses, drive-board supply parts and the common power modules for the brand. For Kawasaki e1294, drive alarms usually stop the whole line, so they sit at the front of our dispatch queue. Before we roll, tell us what Kawasaki e1294 shows on the pendant ERROR HISTORY with AS error numbers (D / E / P prefixes) and what the machine was doing - phone or video triage is free.

This page on Kawasaki e1294 was compiled from actual repair records of the Henghuan Robotics repair team. Alarm notes are our own summary for troubleshooting reference only and may vary with controller and software version — please consult Kawasaki documentation or contact us if in doubt. Henghuan is an independent service provider, not affiliated with or endorsed by Kawasaki.