Written by: Tony Longoria
Modula vertical lift modules (VLMs) protect people, parts, and the machine itself through four layers of safety: user access control, operator protection at the access bay, automatic drawer height detection, and optional fire suppression. Most people know VLMs for the floor space they save. But floor space is only one advantage. The safety and security features built into every Modula VLM matter just as much on your floor every day.
Below, I’ll walk through each feature the way I do during operator training: what it is, how it works, and why it matters on your floor.
How does a Modula VLM control who can access inventory?
A Modula VLM restricts access at the user and drawer level, so each employee can retrieve only the drawers they’re authorized to open. There are two ways to set this up, depending on how your facility operates.
Modula WMS with RFID key fobs
Modula’s Warehouse Management Software (WMS) lets administrators create individual user accounts with unique login credentials. Paired with RFID key fobs, operators badge in with an individually assigned credential instead of typing a password.
With WMS and RFID access in place, you get:
- Individual authentication. Every login is tied to a specific person.
- Drawer-level permissions. Each user can open only the drawers assigned to them.
- Activity tracking. Administrators can see who accessed what, which builds accountability.
- Protection for high-value inventory. Expensive replacement parts, specialized tools, and sensitive components stay secured.
Local Mode on the control console
The Modula control console is the machine’s main operator interface. In Local Mode, administrators can create user accounts and assign drawer permissions directly at the machine, without relying on the WMS for those functions.
For example, maintenance technicians might be authorized for the tooling drawers while production staff are restricted to consumables. Local Mode is a good fit for facilities that want access control without a full WMS rollout, or that need a backup layer of security at the machine.
What protects operators at the VLM access bay?
The access bay, where drawers are presented to the operator, is protected by safety light curtains, an emergency stop, safety-switched service panels, and optional sliding doors. Together, they reduce exposure to moving parts while the machine is running.
- Safety light curtains (light barriers). Light curtains create an invisible sensing zone around the access area. If a hand or body breaks the beam during hazardous machine movement, the safety control system triggers its configured protective response.
- Emergency stop with integrated padlock opening. An accessible e-stop lets operators start a controlled emergency stop the moment something looks wrong. The integrated padlock opening can secure the actuator against resetting, depending on the device design.
- Safety switches on service access panels. The left and right service panels have safety switches that prevent normal machine operation when a panel is opened or removed, depending on the configuration. This limits exposure to internal moving components during service.
- Optional sliding doors. When closed, sliding doors form a physical barrier between personnel and the machine interior. They’re a good addition for facilities that need tighter physical access control.
- High-output LED lighting. An energy-efficient LED fixture provides approximately 5,000 lumens of light on each drawer as it’s presented. Better visibility means faster, more accurate picks and fewer handling mistakes.
Important: The e-stop supports operator safety, but it does not replace your lockout/tagout procedures or dedicated energy-isolation devices during maintenance.
Internal bay vs. external bay: how does VLM safety differ?
The main difference is light curtain coverage: an internal bay uses two vertical light curtains, while an external bay, where the drawer extends out of the machine, uses three to monitor the front, top, and rear of the access area. All other core safety features are the same.
| Safety feature | Internal bay | External bay |
|---|---|---|
| Safety light curtains | 2 vertical | 3: front vertical, upper horizontal, rear vertical |
| Emergency stop with padlock opening | Yes | Yes |
| Service panel safety switches | Yes | Yes |
| High-output LED lighting (about 5,000 lumens) | Yes | Yes |
| Sliding doors | Optional | Optional |
In the external bay, the front curtain monitors the operator side, the upper horizontal curtain detects intrusion from above, and the rear curtain covers the back of the drawer presentation area. Together, they monitor every direction someone could reach in from.
How does drawer height detection prevent damage?
Internal height detection barriers check each drawer’s load as it enters or leaves the access bay, flagging anything that exceeds the permitted storage height before it can hit the machine. It’s one of the features we introduce during initial operator training, because good loading habits protect both your inventory and the machine.
When items are loaded too tall, or stick out past the front or back of the drawer, they can catch on the machine’s internal structure as the drawer moves. Height detection catches the problem at the bay, so the operator can fix the load before it goes back into storage.
That helps you avoid:
- Damaged inventory
- Contact with internal machine components
- Unexpected machine stoppages
- Service calls and downtime caused by poorly loaded drawers
Can a vertical lift module have fire suppression?
Yes. Modula VLMs offer two fire protection options: a built-in electrical fire suppression system and custom roof panels that accommodate a facility’s own water-based sprinkler system.
Integrated electrical fire suppression (optional). This system targets the two most critical electrical areas of the machine:
- The main electrical control cabinet, which houses the components that run the VLM
- The main vertical lift motor, which drives the machine’s vertical movement
Protecting these areas can help limit the consequences of an electrical fire, depending on the installed suppression equipment and fire conditions.
Custom roof panels for water-based suppression (optional). If your facility requires sprinkler coverage inside the VLM, custom roof panels can be configured to accommodate an internal water-based system. The sprinkler system itself is supplied and installed by the customer through a qualified fire protection contractor. We coordinate the roof panel configuration with your installation, subject to the approved design.
Which facilities benefit most from VLM safety and security features?
Any facility storing high-value, sensitive, or tightly controlled inventory gets the most from these features. Common examples include:
- Manufacturing and MRO: spare parts, cutting tools, and specialized tooling that tend to walk off from open shelving
- Aerospace and defense: precision components that require traceability and restricted access
- Healthcare and labs: supplies and equipment where accountability matters
- Government and public safety: controlled equipment that needs a clear record of who accessed it
Frequently Asked Questions About VLM Safety
Are vertical lift modules safe for operators?
Yes. Modula VLMs use safety light curtains, an emergency stop, safety-switched service panels, and optional sliding doors to reduce operator exposure to moving parts. Proper operator training and your facility’s safety procedures are still essential.
What is a safety light curtain on a VLM?
A safety light curtain is a sensing barrier across the access bay. If it detects intrusion during hazardous machine movement, the safety control system triggers its configured protective response. Internal bays use two vertical curtains; external bays use three.
Can you restrict VLM access to specific drawers?
Yes. Modula’s WMS and the control console’s Local Mode both let administrators assign individual users to specific drawers. With RFID key fobs, each operator logs in with their own credential, and access can be tracked.
Does a VLM emergency stop replace lockout/tagout?
No. The emergency stop with integrated padlock opening supports operator safety, but it does not replace approved lockout/tagout procedures or dedicated energy-isolation devices during maintenance.
Can a VLM connect to a facility sprinkler system?
Yes. Custom roof panels can accommodate an internal water-based fire suppression system, which the customer supplies and installs through a qualified fire protection contractor. An optional built-in system also protects the electrical cabinet and lift motor.
The bottom line
A Modula VLM does more than save floor space. It controls who touches your inventory, protects the people working at it, and guards both your stored materials and the machine. The right configuration depends on what you store, who needs access, and your facility’s safety requirements.
Bradford Systems installs, configures, trains, and services Modula VLMs across the United States. Talk to our team about a VLM safety walkthrough and we’ll help you choose the features that fit your operation.
About the author: Tony Longoria is a Service Manager and Installer at Bradford Systems, where he installs VLMs and trains operators on safe, efficient use.
Ready to Talk VLM Safety? We've Got You Covered.
Every facility stores different materials and needs different access rules. Talk with our team about a VLM safety walkthrough. We’ll cover light curtains, user access control, drawer height detection, and fire suppression options for your application.
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