SITRANS F M MAG 5000: Editing Sensor Characteristics After Reset

Overview

The SITRANS F M MAG 5000 is the standard 115/230 V AC or 24 V DC electromagnetic flow transmitter paired with Siemens MAG 1100, MAG 3100, MAG 5100 W, and MAG 6000 I Ex sensors. The transmitter stores the sensor's identity and calibration data in non-volatile memory so that replacement transmitters inherit the sensor curve without re-calibration. Executing the Set to Default command inside the Sensor Characteristics submenu restores the factory-shipped sensor fingerprint and wipes any field-entered Correction Factor and Excitation Frequency override.

This article explains which parameters may legally be edited, which are factory-locked, the access level (Operator / Supervisor / Service) required for each edit, and the exact menu navigation to recover from an unintended default reset. A separate troubleshooting matrix covers the common error states (read-only fields, "Sensor data invalid", HART write errors) that operators encounter after a default command.

Sensor Characteristics Menu Structure

The Sensor Characteristics menu (menu index 2.x in the standard MAG 5000/6000 firmware) contains the following parameters:

Access Levels and Default Passwords

The MAG 5000/6000 firmware implements three hierarchical access levels:

1. Read-only — no password required; view measured values, totalizers, and current parameter set.
2. Operator — password 1000 (default) or 2000 on some firmware branches; allows totalizer reset and zero-point adjust.
3. Supervisor / Setup — password 2000 (default) or 3000; required for Qmax, Correction Factor, Excitation Frequency, output scaling, and most HART/Modbus configuration.
4. Service — password 3142 (default Siemens service code); unlocks Calibration Factor, Sensor Excitation, and firmware-level diagnostics. This password is logged in the audit trail and should be reserved for factory-trained personnel.

To enter a password on the local keypad, hold the ▲ key for 2 seconds to enter the menu tree, navigate to Access, select the desired level, and enter the numeric code. If the wrong code is entered five times consecutively the keypad locks for 10 minutes. If the customer has changed the passwords, retrieve them from HART DD menu path Device / Security / Passwords via a Siemens PDM or SITRANS DTM host.

Why "Set to Default" Resets Sensor Characteristics

The Set to Default command (menu index 2.9 on most firmware revisions) executes three actions in sequence:

1. Restores the factory calibration factor stored in the sensor's EEPROM (the value that was burned in at the Siemens flow lab with the actual wet calibration).
2. Resets the Correction Factor to 1.000.
3. Resets the Excitation Frequency to the sensor-size default (typically 6.25 Hz for DN ≤ 300, 3.125 Hz for DN ≥ 350).

This is expected behavior — the reset is by design so that a transmitter swapped onto a different sensor body starts from a known state. The factory calibration factor is recovered from the sensor EEPROM automatically on the next power cycle, so the meter's accuracy returns to the original calibration curve. What is lost is any field-applied correction factor (e.g., a 1.018 multiplier used to match a prover) and any custom excitation frequency selection made to suppress noise on a low-conductivity or slurry application.

Procedure: Restoring the Correction Factor

1. Power the transmitter for at least 5 minutes so the sensor EEPROM has stabilized.
2. Hold the ▲ key for 2 s → enter the menu.
3. Navigate to Sensor Characteristics → Correction Factor (menu index 2.3).
4. If the value is displayed but not editable, the transmitter is in Read-only mode. Press the ● (select) key and enter the Supervisor password when prompted.
5. Use ▲ / ▼ to adjust the value. Acceptable range is 0.850 to 2.000 in steps of 0.001.
6. Press ● to confirm. The display flashes briefly to indicate the value was written to EEPROM.
7. Verify by navigating out and back into the menu — the new value must persist across a power cycle.

If the value still refuses to change after the Supervisor password is entered, the transmitter firmware has flagged the sensor as incompatible (wrong sensor size programmed for the connected body, or sensor EEPROM read error). See the troubleshooting matrix below.

Procedure: Restoring the Excitation Frequency

Unlike the correction factor, the excitation frequency is a discrete menu selection, not a numeric entry. Available values are fixed by the sensor size and the supply voltage:

1. From the Sensor Characteristics menu, select Excitation Frequency (menu index 2.4).
2. Press ●; the currently active frequency is shown with a tick mark.
3. Use ▲ / ▼ to step through the allowed list. Frequencies not valid for the connected sensor size are hidden automatically.
4. Press ● to accept. The new excitation frequency takes effect within 2–4 excitation cycles (a few seconds at 25 Hz, up to 30 seconds at 1.5625 Hz).
5. Verify on the HART host: variable Primary Variable (PV) should remain stable through the transition; a brief step in the analog output is normal while the coil drive reconfigures.

Why the Calibration Factor Is Editable Only in Service Mode

The Calibration Factor is a four-decimal multiplier (typically between 0.8 and 1.2) printed on the calibration certificate that ships with every MAG 1100, MAG 3100, and MAG 5100 W sensor. Siemens performs a wet calibration of each sensor at the factory against a reference gravimetric or master Coriolis rig. The calibration factor linearises the inherent offset of the sensor coils and electrode geometry; it is not a tuning parameter.

Changing the calibration factor manually causes the following:

• The meter's stated accuracy of ±0.4 % of flow rate (or ±0.2 % with the MAG 6000 in higher-tier variants) is invalidated.
• The traceable calibration record is broken — the device no longer matches the calibration certificate.
• Custody transfer applications under OIML R49, MI-001, or NTEP lose their pattern approval if the calibration factor is edited after the seal is applied.

Verification Checklist After Recovery

1. Power-cycle the transmitter and confirm the entered Correction Factor and Excitation Frequency persist.
2. Compare the live PV (L/m or m³/h as configured) against an independent reference at one flow point between 25 % and 75 % of Qmax. Acceptable deviation: within the published accuracy class for the sensor.
3. Verify zero point: with the line full and flow at absolute zero, perform Auto Zero under Operator access (menu 3.1) and confirm the offset stores at < 1 mm/s velocity.
4. Read back parameters via HART command 3 (Read Dynamic Variables) and HART command 13 (Read Tagged Dynamic Variables) to confirm the host DCS sees the corrected values.
5. Export the final configuration via HART command 162 to the asset database for change-control records.

Troubleshooting Matrix

Field-Commissioning Notes

When commissioning a replacement MAG 5000 transmitter against an existing sensor body:

• Always perform a Set to Default on first install. The transmitter then auto-reads the sensor EEPROM and uploads the calibration factor.
• Document the four key sensor parameters (size, calibration factor, correction factor, excitation frequency) in the commissioning sheet before powering down.
• Apply the Correction Factor only if the customer's master meter reference disagrees with the SITRANS reading by a consistent ratio across multiple flow points. If the offset is non-linear, the sensor has a real issue (electrode coating, liner damage, partially filled pipe) and the Correction Factor will mask it.
• When pairing with a MAG 6000 I Ex (Ex-de) sensor in hazardous areas, the excitation frequency is locked at 6.25 Hz by firmware and is not user-editable.

Related Documentation

Reference the official Siemens documentation set for the MAG 5000/6000 platform:

• SITRANS F M MAG 5000/6000 Operating Instructions (Siemens manual A5E02387356)
• SITRANS F M MAG 5000/6000 Service Manual (factory-only distribution)
• Siemens Industry Online Support knowledge base: support.industry.siemens.com
• SIMATIC PDM device description library for SITRANS F M (DD version 1.2.x and later)
• SITRANS F M product catalogue FI 01 (printed matter E86060-K6201-A101-A4)