Password protect a DirectSOFT project the supported way

Name the thing you are protecting

Three files are in play, and each takes a different measure.

Most requests for a 'password on the app' are really about row one. The guard for a full DirectSOFT project is the controller's password, and the next two sections work it that way.

What a protected save gives you

Saving a project as protected creates a file with the same project name and the .epp extension. The .epp file is closed to editing: the only operation left in it is the download to a panel. That makes it the right output when an operator-interface application is finished and you want the copy handed to the panel to stay closed. It is the wrong choice for a program that still has to be maintained, because once the editable original is gone there is nothing left to maintain from.

So keep the editable master through any protection change. The habit on the HMI side is the same one: enable HMI project protection and keep the editable master.

Set the PLC password the supported way

What you need:

• A verified backup of the project, made before anything changes.
• The manual for your controller family, which prints where the password setting lives, the allowed length and characters, and which actions the password blocks on that model.
• The site's credential procedure and an approved place to record the password.
• A test PC, or an approved maintenance window; a 30-minute window is enough for the password step on one controller, and 60 minutes if you also practice the protected save first.

The job then runs in five steps.

1. Back the project up and prove the backup. Save the project, close DirectSOFT, copy it the way your version stores it, open the copy, and only then change anything.
2. Read the password section of the controller manual. The setting belongs to the controller, reached from the programming software while the PC is connected. The manual for the exact family shows the path and the rules; they differ between families, so no path or password rule is printed here.
3. Set the password against the PLC exactly as the manual's procedure runs. It is a controller setting, not a file trick: renaming files or putting a .epp copy in the project folder guards nothing.
4. Record the credential in the site's approved store and name who may retrieve it. One safety note: have the documented reset path for that controller model in hand before you set the password, because a credential nobody can retrieve stops maintenance, and the only honest recovery is the vendor's own documented procedure.
5. Leave the editable master alone. The PLC password changes the controller, and the project file on your PC stays guarded by the login on that machine and the permissions on the share.

Example: locking one line PLC before a contractor visit

Inputs, and where each comes from:

• One controller carries the line program, written as a full DirectSOFT 5 project. That is the case this article answers.
• Two people touch the program this month: the plant engineer who maintains it, and a panel-building contractor who must not open it. Scenario numbers for this case.
• Three access points exist: the project file on the PC, the PLC link, and the .epp transfer file for a panel. These are the three the software itself separates, as described above.
• One bench PC for the practice run, loaded from the vendor's v6.3 installer, a 42.4 MB download that installs the free DirectSOFT100 tier when no keycode is entered. Documented on the vendor's support download page.
• The contractor arrives in 5 days, so the practice run and the checks below happen at least 1 day before the visit.

The rule in words: one PLC password covers one of the three access points, the controller. The .epp file is a transfer file, not a guard on the project, and the PC project has no open-time password at all.

The arithmetic: of the 3 access points, the PLC password covers 1, which leaves 2 that still need a measure (3 - 1 = 2). The two are covered by ordinary means: the master stays on a machine the contractor cannot log into, and no .epp copy leaves the office while the contractor is on site. The change itself makes 0 edits to the ladder program and leaves 1 editable master in place, and the whole job fits inside a 30-minute window.

The result: a controller that refuses uncredentialed access, an untouched editable project on the engineer's PC, and no transfer file in circulation during the visit.

The decision: while the program must stay editable, the PLC password plus a controlled PC is the whole job, and the protected save never becomes the working file. If a program is finished and only ever goes to a panel, the protected save on its own is enough and the password step can be skipped.

How to check it worked

Run every check on a test copy of the project, or inside an approved maintenance window.

1. From the test PC, attempt the PLC link without entering the credential. The access you mean to block must be refused. If the link goes straight through, stop, re-read the manual's password section, and treat the protection as not live.
2. Connect with the credential and confirm authorized staff can still do their normal work. Prove the path before anyone writes, the same discipline as when you test writes before motion on an operator panel link.
3. Open the editable master on the engineering PC. It still opens, as it should: the PLC password was never about this file.
4. If you keep a .epp transfer file, confirm on the bench that it offers the download to a panel and stays closed to editing.

Budget 15 minutes for the four checks; two people, one at the bench PC and one at the engineering PC, finish them in a single pass.

Write into the site log which access points were tested, with which credential, and on what date.

If the app you mean is the operator interface

A password at open time does exist on the panel side, at the screen level rather than the project level. Password protect an HMI setpoint screen at entry shows the pattern of asking for a credential when a specific screen opens, and protecting the HMI setup menu key path guards the service settings the same way. For a whole operator view with roles, HMI screen access control for a protected operator view covers the wider setup. The finished app then travels to the panel as the protected .epp copy described above.

The decision

Recommendation: when technicians must keep editing the program, set the PLC password on the controller through the vendor's documented procedure, keep the editable master on a machine non-engineers cannot log into, and treat the .epp protected save as a transfer file for panels only. When a program is finished and only ever gets downloaded to a panel, the protected save is enough on its own. In both cases, test the setup with and without the credential, on a copy, before you call it live.

Questions