How to Program a Lathem Sonachron DWA-S Workshift Timer

The Lathem Sonachron DWA-S is a classic workshift timer used to trigger bells, buzzers, or control events on a schedule. It is now discontinued, but many units remain in service because they are simple, dependable, and wired into existing signaling systems. If you still have a DWA-S on the wall, the most common programming hurdle is access: the battery is disconnected, the keypad is locked, or the security code is unknown.

This guide shows an easy, practical way to restore access and program a basic security code (example: MON ? WED ? FRI ? RUN), then return the unit to normal operation. If you’re planning a replacement due to age or parts availability, we’ll also point you toward a modern upgrade path at the end.

Before You Start

• Confirm power: The DWA-S can run on AC power with battery backup. If the battery is disconnected, you may lose programming during outages and some functions may behave unexpectedly.
• Know what you’re securing: The DWA-S can be set so only programming is secured, or so all functions (including manual ring keys) require the code.
• Have a small screwdriver ready: You may need to remove the left side panel to access the dip switches.

Step 1: Make Sure the Battery Is Connected

Open the unit as needed and confirm the internal backup battery is plugged in. The battery connection matters for reliability and helps prevent schedule loss during power interruptions. Once connected, close the unit enough so you can safely power it and read the display.

Step 2: Decide on Security Level (Keep Manual Unsecured)

For most workplaces, the simplest setup is: secured programming, unsecured manual functions. That means managers can ring the bell manually without entering a code, but changes to schedules and settings still require the security code. This is typically the most practical balance for schools, warehouses, and production floors.

Step 3: Set or Change the Security Code (Example: MON ? WED ? FRI ? RUN)

If the display is already prompting for a security code at power-up, you can set it immediately. If the clock is already running and you need to view or change the code, you’ll use the dip switch access method below.

Option A: If the Display Shows “SECURITY CODE”

1. When the unit prompts for the security code, press your chosen day keys in order. Example: MON, then WED, then FRI.
2. Press RUN to save.
3. When prompted, choose UNSECURED MANUAL (recommended for most installations), then press RUN to continue to normal operation.

Option B: If You Don’t See the Security Prompt (Use Dip Switch #2)

This is the fastest way to regain access when you don’t know the code or the keypad is locked.

1. Remove the left side panel to access the dip switches.
2. Toggle Dip Switch #2 (flip it to the opposite position, then back if needed) to force the unit to display the security