How to Choose Between Isolated and Non-Isolated I/O

Q: What does 4000V isolation mean?

It is the withstand rating of the galvanic barrier, the voltage it holds off in a dielectric test, proving its integrity against large transient differences. It is not a continuous working voltage; it is the margin that lets isolated CAN, RS-232/485 and GPIO survive ground-potential differences and surges. BITECH provides 4000V isolation as standard on the AE-3588BT and as a configured option on platforms like the AX-130BT.

Q: Why does BITECH treat isolation as a configured option?

Because the deployment decides whether it is needed. Isolation adds cost and a small amount of interface latency; fitting it where a design has a clean, unified ground wastes both. On the AX-130BT, BITECH fits isolated CAN/RS-485 4000V for motor drives, long runs, vehicle buses and high-EMI floors, and leaves it out for clean cabinet installs. Send your grounding topology and BITECH specifies the right configuration.

Q: Does isolated I/O add latency?

Yes, a small amount, because crossing the barrier adds propagation delay. For most industrial signaling it is negligible against the reliability gained, but where latency is critical, such as AOI or tightly-coupled AGV loops, a non-isolated low-latency design like the AE-3588LBT can be the better choice on a controlled ground.

Isolation isn’t a fixed feature you pay for whether you need it or not. It’s a deployment decision — and on platforms like the AX-130BT, a configured option.

A galvanic barrier is an electrical firewall — it stops ground loops and surges at the interface before they cascade into the core.

BITECH Engineering Notes · ~8 min read

In short: Choose isolated I/O when a signal crosses between different ground references or touches the outside world — AGV/AMR motor-drive networks, long multi-axis cable runs, vehicle power buses, or high-EMI floors. Choose non-isolated I/O for clean cabinet installs with a unified ground plane, where you want lowest latency and cost. At BITECH, isolation isn’t a fixed feature you pay for whether you need it or not — on platforms like the AX-130BT it’s a configured option, fitted where the deployment demands it and left out where it doesn’t.

The I/O stage is where an industrial computer meets the machine — and the machine is electrically hostile. A board that runs cleanly on a bench starts dropping CAN frames, logging phantom inputs, or failing outright once it’s wired to a motor drive, a solenoid bank, or a field sensor down a long cable. Almost always, that difference is one decision made early: isolated or non-isolated I/O.

What isolated I/O does

Isolated I/O places a galvanic barrier between the field side of a signal and the computer’s internal electronics. No direct current flows across it, yet the signal still passes. That barrier is an electrical firewall — it stops ground loops and surges at the interface, before they cascade into the core.

Because there’s no shared conductive path, a voltage difference between the two grounds — or a surge injected from a switched motor — can’t drive current through the computer’s logic. On our isolated platforms this is a 4000V galvanic barrier on CAN, RS-232/RS-485 and digital I/O.

The problem isolation solves: ground loops and surges

Two connected devices are rarely at exactly the same ground potential. Different supplies, long cable runs, and large loads all create voltage differences between grounds. Share a non-isolated signal return across them and current flows through the ground because of that difference, not your data — a ground loop. The results are the classic field failures: corrupted CAN and serial communication, false digital inputs, measurement error, and, when a surge rides in from an inductive load, damaged hardware.

Galvanic isolation cuts that shared ground path. It’s the same engineering behind one of our deployed systems — 4000V-isolated controllers acquiring real-time data from medium-voltage switchgear, surviving ground loops and field surges without downtime.

Isolated vs non-isolated: the trade-off

Factor	Isolated I/O	Non-isolated I/O
Ground reference	Separate / floating each side	Shared common ground
Ground-loop immunity	Yes — breaks the loop	No
Common-mode noise & surge	Blocked at the barrier	Passes through
Signal latency	Small added delay	Lowest
Cost & board area	Higher	Lower
Best for	Motor drives, long runs, vehicle bus, high-EMI	Clean cabinet, unified ground, short runs
BITECH example	AE-3588BT (4000V standard), AX-130BT (option)	AE-3588LBT (low-latency)

The BITECH approach: isolation as a configured option

Most of the industry treats isolation as a fixed either/or per SKU. We treat it as a deployment decision. As stated on the AX-130BT: isolation is a configured option, not a fixed feature — because your deployment decides whether you need it.

For AGV/AMR motor-drive networks, long multi-axis cable runs, vehicle power buses, or high-EMI floors, we fit isolated CAN and RS-485 at 4000V.
For clean cabinet installs with a unified ground plane, we leave it out — and take the cost and the added interface latency out with it.

In practice, we ask for your grounding topology and field-device list and specify the right configuration — rather than selling isolation you don’t need or omitting it where you do.

How this maps across our platforms

Platform	Isolation	Why
AE-3588BT	4000V galvanic isolation on CAN, RS-232/485, GPIO — standard	Harsh, high-noise environments: energy, semiconductor, MV switchgear
AE-760EBT	Isolated DIO / COM	x86 + GPU vision where field I/O still crosses grounds
AX-130BT	Isolated CAN / RS-485 4000V — configured option	Fit for motor drives / vehicle / EMI; omitted for clean cabinets
AE-3588LBT	Non-isolated, low-latency I/O	AOI and AGV with controlled ground, latency-critical

One detail that matters across all of them: our CAN uses native hardware controllers with deterministic timing — not USB bridges — so isolation is added without introducing jitter or reflection errors.

When to choose ISOLATED I/O

Choose isolated I/O if any of these hold — and on a real floor, usually several do:

The I/O connects to motor drives, VFDs, relays or solenoids that inject transients.
Cable runs are long (multi-axis, meters to tens of meters) where ground-potential differences build up.
The system rides a vehicle power bus (12V/24V/36V) or sits in a roadside/outdoor enclosure.
The environment is high-EMI — near drives, welders, or heavy switching.
Connected field devices run from different supplies / grounds.

For CAN, RS-485 and DIO that leave the enclosure into any of the above, 4000V isolation is the right default.

Because we fit isolation per deployment, the fastest path to the right configuration is to send us your grounding topology and field-device list. We’ll tell you which interfaces need 4000V isolation and which don’t — so you’re not paying for isolation you don’t need, or running exposed I/O where you do.

FAQ

What is the difference between isolated and non-isolated I/O?

Isolated I/O places a galvanic barrier between the field side and the computer, so they have separate ground references and no direct current flows between them — the signal still crosses via the barrier. It acts as an electrical firewall, stopping ground loops and surges at the interface. Non-isolated I/O shares a common ground and a direct path, making it cheaper and lower-latency but offering no protection against ground loops, common-mode noise, or surges.

When do I need isolated I/O?

Whenever a signal crosses between different ground references or touches the outside world: AGV/AMR motor-drive networks, long multi-axis cable runs, vehicle power buses, high-EMI floors, or field devices on different supplies. In these cases BITECH fits 4000V isolated CAN and RS-485.

What does 4000V isolation mean?

It’s the withstand rating of the galvanic barrier — the voltage it holds off in a dielectric test. It is not a continuous working voltage; it’s the margin that lets isolated CAN, RS-232/485 and GPIO survive ground-potential differences and surges. BITECH provides 4000V isolation as standard on the AE-3588BT and as a configured option on platforms like the AX-130BT.

Why does BITECH treat isolation as a configured option?

Because the deployment decides whether it’s needed. Isolation adds cost and a small amount of interface latency; fitting it where a design has a clean, unified ground wastes both. Send your grounding topology and we specify the right configuration.

Does isolated I/O add latency?

Yes, a small amount — crossing the barrier adds propagation delay. For most industrial signaling it’s negligible against the reliability gained, but where latency is critical (such as AOI or tightly-coupled AGV loops) a non-isolated, low-latency design like the AE-3588LBT can be the better choice on a controlled ground.

Which BITECH products have isolated I/O?

The AE-3588BT provides 4000V galvanic isolation on CAN, RS-232/485 and GPIO as standard; the AE-760EBT includes isolated DIO/COM; and the AX-130BT offers isolated CAN/RS-485 4000V as a configured option. The AE-3588LBT uses non-isolated, low-latency I/O for AOI and AGV.