An RFQ for a single-axis positioning station must pin six facts on the drive line: supply voltage and tolerance, continuous and peak output current, matched motor family, feedback protocol, functional-safety rating, and fieldbus, otherwise every vendor quotes a different drive and the buyer pays a 15-25% engineering premium during the clarification round [S1][S3][S8].
The envelope is well-defined in 2025-2026 datasheets: low-end positioning axes sit on 230 V single-phase, 100-1500 W drives with 1.16-9.8 A continuous current and 3.5-28.3 A peak [S3], while mid-range 400 V three-phase drives cover 450 W to 55 kW with continuous output from 0.91 A up to tens of amps [S1]. Size the drive first, then bolt the servo motor onto the same datasheet row, or encoder protocol mismatch will force a re-design before commissioning.
Drive voltage class: 230 V single-phase, 230 V three-phase, or 400 V three-phase
230 V single-phase is the default for sub-1.5 kW positioning stations and accepts main-circuit input of 200-230 VAC +10 to -15% at 50/60 Hz with a separate single-phase control supply on the same window [S1][S3]. The Sigma-II SGDH line covers 30-1500 W single-phase with continuous output from 0.44 A to 11.6 A, and the same drives accept 220-230 VAC three-phase on the 0.5-1.5 kW rows [S1].
400 V three-phase is mandatory above 1.5 kW or where the cabinet already has a 400 V bus; HCB-series compact drives accept 3 x 230-480 VAC ±10% at 45-66 Hz and produce a 565 VDC link at 400 VAC mains [S5]. Kinetix 6200/6500 control modules feed power modules on a common DC bus with explicit DC-bus status indicators, which simplifies multi-axis energy sharing [S2]. Pick the voltage class on the available cabinet feeder, not on the motor's nameplate, then verify the drive can deliver the continuous current at that feeder.
Continuous and peak current: the 2-3x rule
Most 2025-2026 servo drives on the market carry a 2- or 3-times peak-to-continuous current rating, and that ratio decides whether the drive survives the acceleration pulse of a point-to-point move [S8]. On the Omron G-Series ML2 line, the 750 W drive (R88D-GN08H-ML2) delivers 4.0 A continuous and 14.1 A peak, a 3.5x ratio, while the 1.5 kW unit pushes 9.8 A continuous against 28.3 A peak, a 2.9x ratio [S3].
On the Sigma-II SGDH line the pattern holds: 750 W outputs 5.7 A continuous, 13.9 A peak (2.4x); 1.5 kW outputs 11.6 A continuous, 28 A peak (2.4x) [S1]. Heidrive's HCB 4/12-3 posts 4 A continuous and 12 A peak, a 3x ratio sized for short, high-accel moves, while the HCB 40/100-3 jumps to 40 A continuous and 100 A peak at the same 3x ratio [S5]. Lock continuous current to the motor's RMS thermal limit and peak current to at least 2x the application worst-case accel current, or the drive will trip I²T during the first 100 ms of every move.
Motor pairing and feedback protocol
Pairing must be datasheet-on-datasheet: the Sigma-II 400 W SGMAH/SGMPH motor line drives only off the SGDH-04AE-OY (0.91 A continuous, 2.8 A peak) on a serial-encoder feedback channel, not off the 750 W or 1.5 kW row [S1]. The Omron G-Series pairs G050-G1K5 cylindrical and GP100-GP400 flat motors with R88D-GN/GT drives on the same incremental/absolute serial encoder channel [S3]. Mixing a G-Series motor with a Kinetix 6500 IAM, or a Sigma-II motor with an Omron G-Series drive, forces a third-party encoder cable or a custom firmware load.
Encoder feedback dictates the drive's feedback port spec: incremental 17-bit absolute serial encoders are now standard on sub-1.5 kW positioning drives, and the 24-bit serial encoder is common above 5 kW. If the axis needs absolute position retention after power-off, write "battery-backed absolute serial encoder" on the RFQ line, not just "absolute", because a multi-turn absolute encoder with no battery option defaults to incremental behaviour after each power cycle [S1][S3].
Functional safety, control loop, and environment
Functional-safety options on the drive's control module gate whether the axis can be CE-marked under the EU Machinery Regulation: Kinetix 6200/6500 control modules ship with built-in Safe Torque-off (STO) on the 2094-EN02D-M01-S0 and 2094-SE02F-M00-S0 SKUs, and the higher -S1 variants add Safe Speed Monitoring [S2]. Drives that lack STO force a separate contactor in the cabinet, which adds a fault path and inflates the wiring diagram by one page.
Operating environment belongs on the RFQ, not in the vendor's footnote: most positioning drives rate 0 to +55°C operating, -20 to +65°C storage, up to 90% RH non-condensing, and 1000 m altitude, with vibration/shock at 5.88 m/s² and 19.6 m/s² respectively [S3]. The control method for positioning-class units is IGBT-driven PWM with sine-wave current output, with a 1 kHz current-loop response on the G-Series ML2 line [S3].
Bus, control architecture, and option modules
Positioning axes are usually one of three control architectures: pulse-train + 24 V digital I/O for standalone stations, analog speed/torque reference for retrofit, or a motion bus for multi-axis machines. Sigma-II accepts analogue speed/torque, pulse-train positioning, and option modules for MECHATROLINK-I/II, DeviceNet, and PROFIBUS [S1]. Omron G-Series splits cleanly: R88D-GT is analog/pulse and R88D-GN is MECHATROLINK-II for CJ1W-NC controllers [S3]. Kinetix 6500 runs Integrated Motion over EtherNet/IP and Kinetix 6200 runs Integrated Motion over Sercos, with the control module's two-port Ethernet vs. one-port Ethernet Sercos distinguishing the two SKUs [S2].
Write the bus protocol on the RFQ as a single line, not as a "preferred" option, or the vendor will quote the analog/pulse variant by default. If the cabinet has a CJ1W-NC or a Rockwell Logix controller, specifying the wrong bus family costs a control-module swap that can double the drive price on small axes [S2][S3].
RFQ line-by-line spec map
Build the drive line in this order, and the vendor's quote will arrive with one drive per row instead of three options. Line 1: Supply, "200-230 VAC single-phase +10/-15%, 50/60 Hz, control supply 24 VDC ±20% separate" or "3 x 400-480 VAC ±10%, 45-66 Hz". Line 2: Output, "Continuous ___ Arms, peak ___ Arms, 2-3x ratio minimum". Line 3: Motor pair, "matched to servo motor family ___ rated torque ___ Nm at ___ min⁻¹". Line 4: Feedback, "17-bit or 24-bit serial encoder, absolute, battery-backed". Line 5: Safety, "STO SIL 2 / PL d minimum" or "STO + Safe Speed Monitoring" [S2]. Line 6: Bus, "MECHATROLINK-II / EtherNet/IP / Sercos / analog+pulse". Line 7: Environment, "0-55°C, <90% RH, <1000 m, panel-mounted".
Spec mistakes that force a requote cycle: omitting peak current (vendors default to 1.5x and undersize), specifying "absolute encoder" without the battery option (defaults to incremental), leaving altitude blank above 1000 m, and naming a bus family without naming the controller that drives it. Lifting these seven lines from the 2025-2026 datasheets and adapting them to a servo positioning axis keeps the quote turn-around under one week and the BOM delta under 5% [S1][S3][S5][S8].
Energy and Ecodesign compliance for European builds
Drives sold into the EU for servo positioning must publish Ecodesign losses under EU 2019/1781, and Rockwell Kinetix publishes a separate Kinetix Servo Drive Performance Specifications per Ecodesign Regulation (EU) 2019/1781 in publication KNX-TD006 [S7]. The same document set is the one to attach to a CE technical file when the axis ships as part of a machinery subassembly, and it pre-empts the "losses not declared" finding that pulls an EU customs entry. Track the next signal: any 2026 Q3-Q4 update to the Ecodesign lot 2 or lot 30 thresholds, and the Sigma-II / G-Series datasheet cross-references for system-level losses, both of which will rewrite the standby-power line on new RFQs [S7].
For related retrofit spec work, the fluid coupling certification checklist covers the same line-by-line RFQ discipline for a different component class, and the magnetic drive pump spec map shows how a sealed-pump line is built with the same seven-line discipline.
Spec-level background on the components involved: servo press.