The Sigmatek DIAS Drive 300 series, which includes the SDD 310 and the SDD 315, is a three-axis servo amplifier that communicates with the machine controller over VARAN. When one of these drives stops a line, the maintenance team needs three things: the electrical ratings, the meaning of the LEDs and status bits, and a clear way to tell an external fault from a failed amplifier. This guide covers each of these using Sigmatek's own instruction manuals (Art. 10-501-101-23E, 10-501-101-3E and 10-501-151-23E) and the SDD 310 and SDD 315 product sheets. It closes with how to send a drive to Flexa Systems for component-level repair.
What the DIAS Drive 300 Is
Sigmatek's product sheet calls the SDD 310 the company's "standard" drive for midrange power. It is a three-axis device rated at 3 x 10 A continuous and 3 x 20 A peak current. An integrated auto-scaling function lets it control small motors, under 1 A rated current, without losing resolution. The SDD 315 uses the same platform with mixed axis sizes. One axis is rated 15 A continuous and 30 A peak, and the other two are rated 10 A and 20 A. This lets motors of different power ranges run from one amplifier.
Both drives communicate with the machine controller over VARAN, which Sigmatek describes as "fast, hard real-time capable and nearly jitter-free." Per the manual, the field-oriented current controller, the speed controller, and the spline-interpolation and position controller each update every 62.5 µs. The drive synchronizes fully to control cycle times of 250 µs, 500 µs and 1-8 ms. The DIAS Drive 300 concept covers 1- and 3-axis amplifiers with two mounting options: on a mounting plate inside the cabinet, or through-hole mounting. A Cold Plate version of the SDD 310 also exists.
The most important point for anyone replacing or repairing one of these drives is that the parameter memory is volatile. The manual states: "After power-up, the parameters are loaded into the servo amplifier via the host." The drive does not keep its own tuning, motor data or limits. The machine's control program supplies them every time the drive powers up. On machines where an S-DIAS CPU such as the CP 112 CPU that hosts the drive parameters is the VARAN master, that controller and its project are what make a drive "configured."
This has two practical consequences:
- A repaired or exchanged amplifier does not need a parameter backup restored from the old unit. It needs a working VARAN connection to a host that holds the correct project.
- If the controller, its storage or its project is the problem, swapping the drive will not fix it. Background on the controller side is in our guide to Sigmatek CP 112 and DIAS modules.
SDD 310 and SDD 315 Ratings
The values below come from chapter 1 of the instruction manuals and from the SDD 310 and SDD 315 product sheets. Unless noted otherwise, the SDD 315 shares the SDD 310 values.
| Parameter | SDD 310 | SDD 315 |
|---|---|---|
| Mains supply | 3 x 230 V -10% to 480 V +10%, 45-65 Hz, TN or TT with grounded neutral | Same |
| Max. symmetrical short-circuit current | 5000 A rms | Same |
| Rated power S1 | 14 kVA | 8 kVA at 230 V; 14 kVA at 400-480 V |
| Axis rated current | Axes 1-3: 10 A rms | Axes 1-2: 10 A rms; Axis 3: 15 A rms |
| Standstill current (after 500 ms) | Axes 1-3: max. 7 A rms | Axes 1-2: 7 A rms; Axis 3: 10.5 A rms |
| Peak current (max. 5 s) | Axes 1-3: 20 A rms | Axes 1-2: 20 A rms; Axis 3: 30 A rms |
| Max. continuous sum current, all axes (heat sink) | 20 A rms | 20 A rms |
| DC link voltage | 290-680 V DC | Same |
| DC link overvoltage protection limit | 450-900 V DC | Same |
| DC link capacitance | 700 µF | Same |
| Inrush peak (charging circuit) | 2.5 A | Same |
| Auxiliary supply +24 V | 22-30 V DC, 35 W, PELV; supply rated 5 A or more | Same |
| Holding brake supply +24 V-BR | 25-27 V DC, max. 2 A DC per axis, 100 mJ switching energy | Same |
| PWM / regulator frequency | 8 kHz / 16 kHz | Same |
| Output stage loss | 10 W per A rms (average of 3 axes) | Same |
| Internal regen resistor | 25 Ω / 200 W | Same |
| External regen resistor | 25-50 Ω | Same |
| Regen at 400 V mains: start-up / switch-off / OV protection | 730 V DC / 690 V DC / 800 V DC | Same |
| Regen at 400 V mains: external resistor max. / internal peak | 1200 W / 21 kW (1 s) | Same |
| Ambient temperature | 0 to +45 °C at rated values; +45 to 55 °C with 2.5 %/K derating | Same |
| Protection / pollution / overvoltage category | IP20 / degree 2 / category III | Same |
A few points from the same manual chapters are useful in the field:
- Single-phase operation. The drive can run on single-phase power, for example during initial start-up.
- Other mains voltages. At 480 V mains the regen thresholds rise to 850/810/900 V DC, with a 1500 W external resistor limit and a 27 kW internal peak. At 230 V they are 420/400/450 V DC, 750 W and 6.5 kW.
- Grounding and RCD. The manuals require a Type B RCD where a ground-fault breaker is used, and a protective earth conductor of at least 10 mm² (8 AWG). Leakage current is up to 15 mA.
- Encoder supply. The 8 V and 5 V encoder supplies on X6/X7/X8 are each rated for a maximum of 250 mA.
- UL reference. The manuals cite UL 508C, file E336350.
Connector layout is as follows:
- X1A: 24 V auxiliary supply (Combicon 5, 3-pole)
- X1B: power (Power Combicon 7.62, 8-pole, 4 mm²)
- X3/X4/X5: motor outputs (Power Combicon 7.62, 6-pole)
- X6/X7/X8: feedback (25-pole female Sub-D, one per axis)
The feedback inputs accept resolver with thermo contact, EnDat and Hiperface (single- and multi-turn), sine/cosine and TTL encoders. Resolver excitation is 8 kHz at 4 V rms, for 2 to 32 poles. The manual limits sine encoder cables to 10 m and gives a TTL upper frequency of 100 kHz.
Variants and Article Numbers
Sigmatek's downloadable documentation covers three DIAS Drive 300 models. Each has its own article number and mechanical design.
| Model | Article number | Construction | Manual |
|---|---|---|---|
| SDD 310-23 | 09-501-101-23 (09-501-101-23X = PCB with protective lacquer) | With fan unit; 472/378 mm high (with/without plugs), 158 mm wide, 240 mm deep, 10 kg | 10-501-101-23E |
| SDD 310-3 | 09-501-101-3 | Cold Plate; 428 x 152 x 121.3 mm, 6.35 kg | 10-501-101-3E |
| SDD 315-23 | 09-501-151 (product sheet: 09-501-151-23) | With fan unit; 472/378 x 158 x 240 mm, 10 kg | 10-501-151-23E |
| VAC 013 (built into DIAS Drive 3xx) | 16-059-013 / 16-059-013-L | Integrated VARAN interface with safety inputs | Chapter 7 of 10-501-101-23E |
On the fan-cooled -23 versions, a controlled internal fan provides forced ventilation. The Cold Plate -3 version relies on the mounting surface to remove heat. The manual requires heat-conducting paste and 0.2 mm planarity on that surface. When a Cold Plate drive is removed for service, the paste and surface condition must be restored on reinstallation. A poor thermal joint shows up later as heat-sink temperature faults.
The SDD310-43 DIAS Drive 310 is a variant that does not appear in the public Sigmatek manuals we reviewed. Distributor listings identify it as article 09-501-101-43, a DIAS Drive 310. We do not state its cooling type, or whether it carries the VAC 013 safety interface, because no Sigmatek document we found covers it. Treat the SDD 310 family ratings above as the reference, and check the nameplate and installation drawings on your machine. Flexa offers the SDD310-43 as a repair service only. We do not currently have a unit for sale. The SDD 310-23, SDD 310-3 and SDD 315-23 are handled the same way: repair and quote on request.
On lifecycle: Sigmatek's current motion lineup lists the MDD 2000 servo system, a modular multi-axis platform, and no longer lists the DIAS Drive 300. The SDD 310 and SDD 315 manuals, however, are still on Sigmatek's downloads page, and two of them were revised in October 2024. For an installed machine, keeping the existing drive running through repair is usually the most direct path. It avoids re-engineering the control project.
Reading the Two LEDs and the VARAN LEDs
The front of the drive has one green and one red status LED. Their combinations, from section 5.2 of the manual, are below. Codes and meanings can vary by model, firmware and catalog number, so confirm against the drive's own manual before acting on them.
| Green LED | Red LED | Meaning |
|---|---|---|
| On | On | Controller in boot mode (firmware damaged or not available) |
| 1 Hz flashing | Off | Ready to start |
| 8 Hz flashing | Off | Output current limited by I²t (one or more axes) |
| On | Off | Operation |
| On | 1 Hz flashing | Warning |
| Off | On | Error |
The integrated VAC 013 interface has its own LEDs for the VARAN IN and VARAN OUT ports. Each port has two:
- LINK (green): indicates a physical (PHY) connection.
- ACTIVE (yellow): indicates data exchange.
If LINK is off on VARAN IN, check the cable, the RJ45 connectors and the upstream device; the maximum segment length is 100 m. If LINK is on but ACTIVE is not, the physical layer is up but no data is moving. In that case, look at the controller and its project before suspecting the drive. Because the drive receives its parameters from the host, a VARAN problem can look like a dead amplifier.
Status Register Error Bits
Detailed diagnosis uses the 32-bit status register I-STATUS (manual section 5.2.3). The masks G-MASKE1/E2/W/D determine whether each condition is treated as an error, a warning or ignored, so the same event can stop one machine and only warn on another. The table groups the documented bits by area.
| Bit | Condition | What to check (per manual) |
|---|---|---|
| Supply and DC link | ||
| 0 | Single-phase operation | Mains phases at X1B, fuses, contactor |
| 1 | Main-supply error | Drive enabled without mains, or before the DC link was charged; check enable sequencing |
| 3 | DC over-voltage | Regen resistor missing or defective |
| 4 | DC under-voltage | Mains level and stability, supply wiring |
| 22 | DC over-voltage and regen limit reached | G-MBAL setting; use an external regen resistor |
| 29 | Total power limit reached | Load profile across all axes versus drive rating |
| Brake | ||
| 6 | Holding-brake error | M-BRAKE=1 but no brake connected, or brake short circuit |
| 7 | Brake-switch error | Internal brake switch defective; the manual says replace the amplifier |
| 23 | Brake supply 24 V-BR missing | +24 V-BR supply and wiring |
| Temperature | ||
| 9 | Motor temperature | Motor thermo switch, or broken feedback cable |
| 10 | Ambient (internal) temperature | Cabinet temperature, ventilation, fan on -23 versions |
| 11 | Heat-sink temperature | Airflow, fan, cold-plate contact, load versus sum current |
| 26 | Motor-temperature warning | A-TEMPMW threshold, motor load and cooling |
| 25 | I²t error | A-I2TERR; mechanical load, duty cycle, tuning |
| Feedback and motion | ||
| 12 | Feedback error | Cable broken, encoder defective or bad connection |
| 13 | Commutation error | M-ROFF, motor and feedback wiring |
| 14 | Motor overspeed | Speed exceeded 1.2 x V-NMAX |
| 15 | Drag (following) error | P-PEMAX limit, mechanics, tuning |
| 16 | Trajectory error | Setpoint above 10000 rpm |
| 27 | Motor parameter error | M-parameters not found in the EnDat/Hiperface encoder |
| 28 | Multi-turn error | More than 4096 turns |
| Communication and safety | ||
| 17 | Host communication | No new setpoints for 2 cycles; check A-CTIME, control cycle time, I-DERROR |
| 20 | Enable locked | Software enable issued while a safety input is low |
| 21 | Driver voltage error | LOCK signal low |
| Internal amplifier errors | ||
| 18 | Amplifier error E2 | Internal; read I-DERROR, contact manufacturer |
| 19 | Amplifier error E1 | Internal; includes power-output ground faults in motor or cable, defective output stage, regen-circuit faults; read I-DERROR |
Firmware 1.82 and later also limit the electrical rotary-field frequency to 599 Hz. Status bit 18 is set if that limit is exceeded for more than 1 s. Before reading bit 18 as an internal fault, confirm the firmware level and the commanded speed against the motor pole count.
Errors That Mean the Amplifier Needs Repair
Most DIAS Drive faults come from outside the amplifier: wiring, motors, feedback, the regen resistor, the 24 V supplies or the controller. A small set of conditions points inside the drive. For broader context, see our article on servo drive symptoms and when to fix or replace.
Conditions that point inside the drive
- Bit 7, brake-switch error. The manual is direct: the internal brake switch is defective, so the amplifier must be replaced. Before concluding this, rule out bit 6 (external brake short or missing brake) and bit 23 (missing 24 V-BR). If bit 7 persists with a known-good brake circuit, the switching stage on the drive needs repair.
- Bits 18 and 19, amplifier error E2 and E1. These are internal errors, and the manual says to read I-DERROR and contact the manufacturer. E1 also covers ground faults on the power output in the motor or cable, so separate the two first. Disconnect the motor cable at X3/X4/X5, reset the drive and enable it. If E1 returns immediately with no cable attached, the fault is in the output stage or regen circuit. If E1 clears, test the motor and cable insulation.
- Both LEDs on (boot mode). The controller is in boot mode because firmware is damaged or not available. A firmware reload may recover the unit. If boot mode returns after power cycling, or the drive cannot be reloaded, the control board or its memory needs bench repair.
- DC over-voltage (bit 3) with a good regen resistor. The manual's first remedy is a missing or defective regen resistor. Measure the resistor and compare it with the documented values (internal 25 Ω; an external resistor must be 25-50 Ω) and check its wiring. If the resistor and wiring are good, bit 22 (regen limit) is not set, and the drive still trips on over-voltage during normal braking, suspect the internal regen switching circuit. That is one of the faults that bit 19 E1 covers.
Wiring, motor and tuning causes
The typical malfunction table in section 5.2.2 lists symptoms that are almost always outside the amplifier:
- Motor does not rotate: check the U/V/W motor connections.
- Motor "spins through": check M-ROFF (commutation offset).
- Motor stops at certain positions: check M-POL / M-RPOL, or look for a broken motor cable.
- Motor oscillates: reduce V-KP / P-KV, and check the feedback-cable shield.
Feedback errors (bit 12) and motor temperature errors (bit 9) also often trace to the 25-pole feedback cable, because a broken wire can interrupt the thermo contact signal as well. Swapping a feedback cable to a neighboring axis on the same drive is a quick way to see whether the fault follows the cable or stays with the channel. Our summary of what fails inside industrial drives explains why power stages, regen circuits and supply sections deserve attention once external causes are ruled out.
Before any work on the drive, isolate the mains and the 24 V supplies. Lock out the equipment, and allow the 700 µF DC link to discharge. Verify that the DC link is at zero before touching X1B or the motor terminals.
STO and SS1 on the VAC 013 Interface
On the drives covered by manuals 10-501-101-23E and 10-501-151-23E, the VAC 013 module is built in. It provides:
- VARAN In and VARAN Out
- Four fast digital inputs, usable as position latches
- Two safety inputs, ENABLE_H and ENABLE_L
- One normally open relay output (S3/S4) that reports safety-function status. This relay is not itself a safety output.
The safety inputs implement two functions:
- STO (Safe Torque Off): described in the manual as "safe restart."
- SS1 (Safe Stop 1): stop category 1 per EN 60204.
The documented safety ratings are:
- SIL 3 per EN 62061 / IEC 62061
- PL e, Category 4 per EN ISO 13849-1
- DC 99 %
- PFHd 0.29 x 10^-9 /h
- MTTFd 8694 years
- Service life of 20 years
The approvals listed are CE and "TÜV-Austria EG Type Tested."
The safety inputs are differential, ENABLE_H(+) and ENABLE_L(-), at typically 24 V and a maximum of 30 V. Turn-on takes about 20 ms, and turn-off takes 0.5 to 1 s. SS1 has a typical turn-off delay of 0.5 s. Actions that depend on STO, such as manual access to the machine, may be released only after 1 s.
The holding brake is not part of the safety function. The manual states: "The stop brake control is not a component of the safety function." To shut the brake off safely, the +24 V-BR supply must also be switched off externally. Hanging or vertical loads need additional measures. Keep this in mind when assessing a machine after an amplifier swap or repair.
Two troubleshooting notes:
- Bit 20 "Enable locked" means the software enable arrived while a safety input was low. This is usually a sequencing or safety-circuit condition, not a drive failure.
- The Cold Plate manual (10-501-101-3E) has no VAC 013 or STO chapter. Whether the Cold Plate or SDD310-43 variants carry STO is not confirmed by the documents we reviewed. Verify on the unit itself before relying on it.
Sending a DIAS Drive to Flexa for Repair
Flexa Systems is an independent supplier of new and refurbished industrial automation parts. We are not affiliated with Sigmatek. We repair DIAS Drive 300 amplifiers at component level through our servo drive repair service. Component-level work means diagnosing and replacing the failed parts, such as power semiconductors, regen and brake switching circuits, supply sections and control electronics, rather than swapping whole boards.
To speed up diagnosis, include the following with the drive:
- The full model and article number from the nameplate (for example 09-501-101-23 or 09-501-101-43)
- The LED state at the time of failure (green and red, steady or flashing)
- The active I-STATUS bits and, for bits 18 or 19, the I-DERROR value read through the controller
- Which axis or axes were affected, and whether the fault returned with the motor cables disconnected
- The mains voltage and whether an external regen resistor is used
- Whether the drive uses a fan unit or a cold plate, and whether the safety inputs are wired
You do not need to send parameter files. The drive keeps no permanent configuration, and the machine's control reloads parameters at power-up. You also do not need to send the motors or cables unless we ask for them for a specific diagnosis.
To get started, request a repair quote with the details above. Repairs are covered by our 2-year warranty terms. If a machine is down, ask about our rush repair service when you submit the request. For the controllers and I/O around the drive, see our range of Sigmatek parts and modules. For other drive platforms in your plant, you can browse our servo drives in stock.
Call Flexa Systems at (254) 254-0005 to discuss a DIAS Drive 300 repair or to arrange shipping.
Frequently Asked Questions
Does a repaired SDD 310 need to be reprogrammed before it runs?
No parameter file needs to be restored to the drive itself. Sigmatek's manual states that the DIAS Drive 300 parameters are loaded into the servo amplifier by the host after power-up. As long as the machine controller holds the correct project and the VARAN connection works, the controller configures the repaired or exchanged drive automatically each time it starts.
What does it mean when both LEDs on a DIAS Drive are on?
Green and red both on means the controller is in boot mode, because the firmware is damaged or not available. A firmware reload can sometimes recover the drive. If the drive stays in boot mode after power cycling or cannot be reloaded, the control electronics or their memory usually need bench repair at component level.
Is a brake-switch error on the SDD 310 always a failed drive?
Status bit 7, brake-switch error, means the internal brake switch is defective, and the Sigmatek manual says to replace the amplifier. First rule out bit 6, an external brake short or missing brake, and bit 23, a missing 24 V-BR supply. If bit 7 persists with a known-good brake circuit, the drive's brake switching stage needs repair.
Does the holding brake count as part of the STO safety function?
No. The DIAS Drive manual states that the stop brake control is not a component of the safety function. For safe brake shutdown, the +24 V-BR supply must also be switched off externally, and hanging loads need extra measures. STO and SS1 through the VAC 013 interface are rated SIL 3 and PL e, Category 4.
What warranty applies to a DIAS Drive repaired by Flexa?
DIAS Drive 300 amplifiers repaired by Flexa Systems at component level are covered by a 2-year warranty, under the terms published on our warranty page. Flexa is an independent repair provider and is not affiliated with Sigmatek. Include the nameplate article number, LED state and active I-STATUS bits when requesting a quote for faster diagnosis.
