SIPROTEC 4: DIGSI 4, configuration matrix and CFC

Short answer

In a SIPROTEC 4 almost everything goes through the DIGSI 4 configuration matrix: each item (indication, measurement, command) is assigned to inputs, outputs, LEDs, buffers or CFC logic. CFC is the graphic gate editor for interlocking and limit supervision. This guide explains the source-destination model, the rules the manual states and the risks of changing the configuration on a relay in service.

Two tools inside DIGSI 4

DIGSI 4 is the program used to parameterize SIPROTEC 4 and SIPROTEC Compact relays. Its system manual describes two parts that are worth keeping apart:

The configuration matrix, which decides which relay component each item of information goes to.
The CFC editor (Continuous Function Chart), which lets you draw your own logic with gates.

The two are directly linked: whatever enters or leaves a CFC logic is first declared in the matrix. Anyone who understands the matrix solves most SIPROTEC 4 problems. To see where DIGSI 4 fits among the Siemens tools, read the guide on Siemens DIGSI software. To go further: Siemens 7SA522, 7SA611 and 7SA612 relays.

The matrix: information, source and destination

According to the manual, an item of information is not only a measurement. It includes measured values, counters, indications, commands and also the quantities used by CFC logic.

The matrix assigns each item to relay components: binary inputs and outputs, LEDs, buffers, display screens and others. Each assignment also sets a type: an indication, for example, can go to a latched or an unlatched LED.

Source: an event generates the item.
Destination: the item is passed on or triggers a reaction.

The relay leaves the factory with default assignments on the front LEDs, some function keys and the binary inputs and outputs. Most can be changed. The matrix has a plausibility check that prevents wrong configurations. Which combinations exist depends on the relay type and the chosen functions.

Rules the manual states

These rules explain errors that keep coming back:

A single-point indication cannot be assigned to several binary inputs. If it is assigned to a second one, the first assignment is removed.
An indication cannot be assigned to a binary input if it is already assigned to CFC as a source. The program answers with an error message. The same happens the other way round.
A double-point indication takes two consecutive binary inputs. If one is removed, the other is also left unconfigured. It cannot be assigned to the last input because there would be no second one. The order of the channels is fixed and the OFF indication always comes before the ON indication.
For an item to enter the logic it must be configured as CFC (destination). To use the logic result elsewhere it must be configured as CFC (source).

CFC: graphic logic for interlocking and supervision

The manual describes CFC as a DIGSI 4 application for creating logic links graphically, such as interlocking conditions or limit control of measured values. The relay already carries some device-specific CFC functions in its basic parameterization.

For your own logic, the editor offers:

Generic gates (AND, OR, NAND and similar).
Analog elements designed for control, for example UPPER_SETPOINT and LOWER_SETPOINT.

The manual cites three uses: station-specific checks, messages when a measured value reaches a critical value and group messages for the higher-level control center. The steps are: open the relay’s CFC chart, place the gates, connect inputs and outputs to the items in the matrix, compile and load the logic into the device.

The details of creating, compiling and loading are in a separate manual, the DIGSI CFC manual, which the system manual cites as a reference. If you need a gate this guide does not cover, consult that document.

Working with the relay: offline and online modes

When a device is opened in DIGSI 4, an operating mode is chosen:

Mode	Used for
Offline	Working with the data saved on the computer
Direct	Connection through the computer’s serial interface
Modem connection	Device connected through a modem
PROFIBUS FMS	Communication over PROFIBUS FMS
Ethernet	Communication over Ethernet

On protection of changes, the manual states that online changes to the configured parameters and the CFC configuration are protected by the parameter-set password, and changes to individual parameters by the individual-parameter password.

Good practices drawn from the manual

Back up before touching the matrix. The manual itself recommends saving the message buffers and the statistics counter.
Work offline first and load into the device when the logic compiles without errors.
Review the whole matrix after every CFC change, because an item may be taken by a binary input and block its use as a logic source.
Document which items are sent to CFC and which outputs depend on them, so the next engineer does not have to deduce it.
Keep the project file as a backup; comparing it with the relay avoids surprises, as explained in relay without documented settings.

What cannot be checked without the software

The specific menus of each DIGSI 4 version, the gates available for each relay type and the behavior of the logic after loading are verified with the software and the relay. This guide collects what the system manual states and gives no setting values or logic templates. To go further: case of a project opened with another software version.

We help with SIPROTEC 4 relays

If you need to modify the logic of a SIPROTEC 4, recover a project or document the matrix of a legacy relay, our team does it remotely, with backups before and after. See the remote configuration of Siemens SIPROTEC relays. See also Siemens 7UT612, 7UT613 and 7UT63 relays.

References

Siemens, SIPROTEC 4, System Description (E50417-H1178-C151), chapters on information configuration, CFC and operation.
Siemens, DIGSI 4 Product Information V4.92.

Frequently asked questions

What does it mean to configure an item as source or as destination?

According to the SIPROTEC 4 system manual, configuring an item as a source means an event generates it. Configuring it as a destination means it is passed on or triggers a reaction, such as lighting an LED, activating an output or entering a CFC gate.

Can the configuration matrix be changed from the relay panel?

No. The manual states that the matrix can only be edited with DIGSI 4. The relay display shows the configuration but does not allow changing it.

What is lost when the configuration of a relay in service is changed?

The manual warns that changing the configuration can lose messages and statistical values from earlier events. It therefore recommends first saving a copy of the operational message buffer, the fault message buffer and the statistics counter.