Replacing Your Acu-Rite DRO Console with TouchDRO

Why Replace Your Acu-Rite Console with TouchDRO?

For most Acu-Rite owners, the valuable part of the system has always been the scales. When the console fails, ages out, or just starts limiting you, you really have three paths: another Acu-Rite, a budget Chinese DRO, or TouchDRO. Here's how they compare:

• Keep the scales you already trust. TouchDRO reads Acu-Rite SENC, ENC, and Mini-Scale glass natively, including reference marks. You don't need to replace your scales or touch the existing installation — only the console gets swapped out, for a modern, high-quality DRO.
• A better answer than another Acu-Rite. A used II, III, or Master MP is just another aging box with no parts pipeline behind it. A new DRO 100 or VUE will cost you $1,500+ for a multi-axis setup. TouchDRO gives you modern, actively supported electronics for a lot less, without either tradeoff.
• Better long-term value than a Chinese DRO. A $200–$400 eBay unit is cheaper than TouchDRO plus a tablet, but that's not the whole comparison. Most budget DROs ship with their own scales — going that route means scrapping your Acu-Rite glass to save on the console. Reusing your existing scales is hit-or-miss too; many budget units aren't built to handle differential TTL cleanly. Either way, you're trading active development, firmware updates, and real support for generic throwaway electronics.

Acu-Rite Scales and Connectors at a Glance

Acu-Rite has produced more than 25 console models over 50+ years, but fortunately almost all of them output a 5V quadrature signal (single-ended or differential), regardless of connector type. The rest is mostly a matter of which physical connector is on your scales.

Connector	DRO Model	Era	TouchDRO Compatible?
9-pin D-Sub, TTL	DRO100 / DRO203 / DRO300, VUE, 200S, 300S, DRO 100S GP/M/T, original DRO 100 / 200 / VRO 300	1997–present	Yes — direct plug-in *
6-pin MS (twist-lock), TTL	Master, EDMVISION, QuickCount, Acu-Rite II / III / L / 5, MillVision, TurnVision, PRO	1968–1992	Yes — with adapter cable or connector swap
6-pin Mini-DIN, TTL	MICRO-LINE Mill, Turn	2001	Yes — with connector swap or adapter

Acu-Rite Scale Connectors

9-Pin D-Sub Connector (Modern)

Acu-Rite scales made since about 1997 use a 9-pin D-Sub connector, similar to the one shown below. This includes the ENC and SENC scale series that shipped with the VUE, 200S, 300S, and the current DRO100 / DRO203 / DRO300 consoles. Most of these scales output a differential TTL signal, but scales that shipped with the DRO 100S — as well as some lower-priced Anilam consoles — output a single-ended signal instead.

Acu-Rite SENC scales are one of the most popular scale options among TouchDRO users, so we offer our TDA-410 milling machine and TDA-420 lathe adapter kits pre-configured for the Acu-Rite pinout. The adapters read both single-ended and differential TTL, and can use the scale's reference pulse to re-establish absolute position after a power cycle.

For reference, the Acu-Rite DB-9 scale pinout is as follows:

Pin 1 is unused. Differential scales populate all eight signal pins; single-ended scales omit the inverted channels on pins 3, 5, and 9.

6-Pin MS Twist-Lock Connector

Acu-Rite consoles built through the 90s — from the original Acu-Rite 5 in 1968 through the Master G/MP/TP and EDMVISION era in 1992 — used a 6-pin MS-style (military-spec) twist-lock round connector. These scales are often referred to as "Acu-Rite Mini-Scales."

These scales output a standard TTL-compatible quadrature with a 5V signal level. They are electronically compatible with TouchDRO, but require either a simple adapter cable or a connector replacement.

In order to use these scales with TouchDRO, you can purchase a pre-made TDC-MS6 adapter cable from us, replace the stock connector with a D-Sub 9 male jack, or build an adapter cable yourself using an Amphenol PT06E-10-6S-SR plug.

The pinout of the scale connector is as follows:

Mini-DIN 6-Pin Connector (MICRO-LINE)

The MICRO-LINE Mill and Turn, introduced in 2001, are the odd ones out in the Acu-Rite lineup. These compact readouts shipped with scales that use a 6-pin Mini-DIN connector instead of the D-Sub or MS connectors found on every other Acu-Rite console.

Electrically, these scales output a standard 5V TTL quadrature signal and are compatible with TouchDRO. Only the physical connector stands in the way.

To use MICRO-LINE scales with TouchDRO, you can either replace the Mini-DIN plug with a DB-9 male jack directly, or build a short Mini-DIN-to-DB-9 adapter cable. 6-pin Mini-DIN plugs can be harder to source than standard D-Sub connectors, so most people find it simpler to cut off the original connector and solder a DB-9 on in its place.

The pinout of the scale connector is as follows:

Most MICRO-LINE scales don't actually populate the reference track. The console supports the reference input and pin 5 is reserved for it, but only a few international scale models carry the signal — for most MICRO-LINE scales, pin 5 is unpopulated and can be skipped in the adapter wiring.

Frequently Asked Questions

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Can I replace an Acu-Rite DRO console without replacing the scales?

In most cases, yes. Acu-Rite SENC glass scales (the 9-pin D-Sub units made from 1997 onward) output standard 5V TTL quadrature and connect directly to a TouchDRO TDA-410 or TDA-420 adapter board ordered with an Acu-Rite pinout. Older 6-pin MS twist-lock scales also output TTL and can be used with an adapter cable or a connector swap. The exception is the 1990 MillMate and TurnMate series, which use an analog 11µA current-loop signal that isn't compatible with modern TTL-based DROs.

Can I use my existing Acu-Rite SENC scales with TouchDRO?

Yes. SENC scales use a 9-pin D-Sub connector and output 5V TTL quadrature — exactly what the TouchDRO Acu-Rite pinout expects. Plug the scales directly into a TDA-410 or TDA-420 adapter board ordered with the Acu-Rite pinout option. No adapter cable, connector swap, or rewiring is needed.

Do Acu-Rite Mini-Scales work with TouchDRO?

Yes. Acu-Rite Mini-Scales from the 6-pin MS twist-lock era output 5V TTL quadrature, which TouchDRO can read. Because the TouchDRO adapter uses DB-9 inputs, you'll need either an adapter cable (6-pin MS to DB-9) or a direct connector swap on the scale cable. The pinout is documented above.

What connector do Acu-Rite scales use?

Acu-Rite used three connector types for TTL scales: a 6-pin MS twist-lock (Amphenol PT06E-10-6S-SR) from 1968 through the early 1990s, a 6-pin Mini-DIN on MICRO-LINE scales introduced in 2001, and a 9-pin D-Sub on SENC and ENC scales from 1997 to the present. All three are TTL and work with TouchDRO. A separate 9-pin D-Sub connector was also used on the 1990 MillMate and TurnMate, but that one carries an analog current-loop signal and is not interchangeable with the SENC D-Sub even though the shell is the same.

Can I replace my MillMate or TurnMate console and keep the scales?

Unfortunately, no. The 1990 MillMate and TurnMate scales output an 11µA analog current-loop signal rather than TTL, and no common modern DRO reads that signal directly. The practical path is to replace the scales with modern TTL units (Acu-Rite SENC or equivalent) and pair them with a TouchDRO. The mounting hardware and cable routing from the original installation can usually be reused.

Will I lose accuracy switching from an Acu-Rite console to a tablet?

No. Positional accuracy is determined by the scales, not the display. TouchDRO reads the same quadrature signal the Acu-Rite console did and counts it at full resolution, so a 5µm or 10µm scale still reports 5µm or 10µm on the tablet. The display only shows what the scales report.