Siwatool FTC Software: FTC_B vs FTC_L Selection and Upgrade

Overview

Siwarex FTC is the Siemens weighing electronics platform used inside SIMATIC S7-300, S7-400, ET 200M, and standalone panels for belt scales, loss-in-weight feeders, and differential dosing applications. The Siwatool parameterization software is the Windows-based commissioning and service tool that exposes the full Data Record (DR) tree, calibration routines, filter design, and diagnostics of the FTC module over an RS-232 point-to-point link. Two distinct Siwatool executables exist: Siwatool FTC_B for belt-scale firmware images and Siwatool FTC_L for loss-in-weight firmware images. The two packages are not interchangeable. They address different firmware branches inside the same Siwarex FTC hardware and only display Data Records (DR) and calibration steps that the connected module's firmware actually implements.

Engineers who attempt to commission a loss-in-weight feeder (DR6 "Loss in Weight Parameter 1" and the related DR7..DR10 loss-in-weight records) with Siwatool FTC_B will see a missing-data dialog, a hidden DR6 row, or an "unknown DR" warning. This is not a version limitation that can be fixed by upgrading FTC_B from V2.1.9 to V2.3.1: even the latest FTC_B release intentionally suppresses loss-in-weight records because the connected module's belt-scale firmware does not compute them. The correct remediation is to install and license Siwatool FTC_L against the same FTC module after loading loss-in-weight firmware into the module.

Siwatool Product Family Architecture

Siwatool is a Siemens-developed, free Windows utility (with an optional licensed full version for loss-in-weight and dosing) that wraps the Siwarex FTC's RS-232 maintenance protocol. The product tree is intentionally split so that the parameterization screen reflects only the data records the loaded firmware variant implements:

Both editions share the same installer shell, the same RS-232 driver, the same DR0..DR5 system records, and the same calibration wizard shell. They differ in which application records (DR6 onward) are visible and editable. Loading a belt-scale firmware into an FTC module and then opening it with Siwatool FTC_L therefore produces a "module type mismatch" warning; loading loss-in-weight firmware and opening it with FTC_B produces hidden record rows. The Siwatool version (V2.1.9 vs V2.3.1) is orthogonal to the FTC_B / FTC_L choice: V2.3.1 simply refreshes the installer, the module firmware loader, and the filter-design math to current Siemens field-service revisions.

Siwarex FTC Module Hardware Variants

The Siwarex FTC is a single hardware platform, distinguished at firmware load time. Two firmware images are field-loadable:

• Belt-scale firmware (FTC_B): Computes belt speed (via encoder or frequency input), material weight per meter, and integrator totalization (kg, t, t/h). Designed for constant-belt-speed conveyors with load cell + speed sensor topology.
• Loss-in-weight firmware (FTC_L): Computes differential weight loss over fixed time intervals, screw or vibratory feeder control output, and refill-cycle handling. Designed for refillable hopper feeders.

Both images are written to the FTC module through Siwatool itself, via the "Firmware Update" dialog inside the tool. After a firmware switch, the module performs a cold start and the Siwatool connection must be re-established; old calibration data is discarded unless explicitly exported first.

Data Record Map: Why DR6 Disappears Under FTC_B

Siwatool exposes module parameters as numbered Data Records (DR). The first records are shared across both firmware images, while application-specific records differ:

If the Siwatool FTC_B V2.1.9 install does not show DR6, the operator must verify two things before assuming a software defect: (a) confirm that the module is currently running loss-in-weight firmware, not belt-scale firmware, by reading DR0; (b) confirm that the Siwatool executable in use is the FTC_L edition. DR6 cannot be added to FTC_B by patching V2.1.9 to V2.3.1 because the record does not exist in the belt-scale firmware image that FTC_B serves.

Choosing the Correct Software Path

Use the decision flow below to identify the correct Siwatool edition for any given application:

1. Identify the physical installation: conveyor with load cell + speed/encoder sensor = belt scale application. Refillable vessel with load cell + feeder actuator = loss-in-weight application.
2. Open the connected Siwarex FTC module and read DR0. The "Application" field returns either "BeltScale" or "LossInWeight".
3. If DR0 reads "BeltScale": install Siwatool FTC_B (latest public release). DR6 will not be visible and should not be expected.
4. If DR0 reads "LossInWeight": install Siwatool FTC_L (licensed). DR6 and DR7..DR10 become available and editable.
5. If DR0 is blank or the firmware is corrupt: load the appropriate firmware image through Siwatool's "Firmware Update" dialog, then proceed.

Siwatool Version History and Upgrade Path

The current public Siwatool FTC_B installer at the time of writing is V2.3.1; V2.1.9 is an older field revision that ships with some SIMATIC PCS 7 V7.x installations and several legacy S7-300 starter kits. The version upgrade is independent of the FTC_B / FTC_L choice and follows the same procedure on both editions:

Upgrade Procedure

1. Back up all DR tables to disk: File → Export Data Records → <filename>.drb. The export captures DR0..DR13 (whichever exist) including scale calibration and filter coefficients.
2. Exit Siwatool completely. Both editions share the same Windows registry hive and cannot run side-by-side during install.
3. Run the newer Siwatool installer (V2.3.1 or later). The installer detects the prior edition and performs an in-place upgrade. No driver re-install is required because the RS-232 service runs as a Windows service registered under the same GUID.
4. Re-launch Siwatool and reconnect to the module. Verify DR0 still reports the correct application ("BeltScale" or "LossInWeight") and that the firmware CRC matches the pre-upgrade value.
5. If the upgrade is from FTC_B to FTC_L (license-driven switch), uninstall FTC_B first, then install FTC_L with the licensed media. A pure V2.1.9 → V2.3.1 bump within the same edition is a standard in-place upgrade and does not require uninstall.

After any upgrade, perform a verification round: read DR0 (module identity), DR1 (calibration), DR3 (load cell), and either DR6 (loss-in-weight) or DR11 (belt speed) depending on application. Compare the values against the exported backup. Any drift on load-cell calibration indicates that the upgrade also rewrote the EPROM; in that case re-enter zero and span from the export file.

Ordering and Licensing Siwatool FTC_L

Siwatool FTC_B is freely available as a demo from the Siemens Industry Online Support portal and ships on the SIMATIC Documentation DVD. Siwatool FTC_L is a licensed product: there is no demo, evaluation, or trial build. The licensed package is delivered as a USB dongle or as a software license file tied to the host PC's MAC address, depending on the order.

To purchase 7MH4900-3AK02, contact the local Siemens Industry representative or submit a quote request through the Siemens Industry Mall. Provide the host PC identifier (PC name or MAC) so the license file can be keyed. Siemens will deliver a license activation file plus the installer media (or download link) within the standard lead time. After installing FTC_L, confirm the "Help → About" dialog reports "Siwatool FTC_L, Licensed <host ID>" rather than "Demo / Limited".

RS-232 Connection and Module Bring-Up

Siwatool communicates with the FTC module over a dedicated RS-232 maintenance port. The connection is point-to-point: one PC to one module. The wiring is a null-modem (crossover) cable with the following pinout for the standard Siemens cable 6ES5734-1BD20 (1.5 m):

Default Siwatool COM settings: 19200 bit/s, 8 data bits, no parity, 1 stop bit, no flow control. The link is established by clicking "Connect" in Siwatool once the module has completed its boot sequence (approximately 8 s after power-up). On successful link, the LED on the FTC module shows steady green and Siwatool populates DR0 with the module serial and firmware ID.

Commissioning Workflow for a Loss-in-Weight Application

1. Confirm the FTC module is loaded with loss-in-weight firmware (DR0 → Application = LossInWeight). If not, use Siwatool FTC_L → Firmware Update to load the L image.
2. Configure load cell: DR3 → enter load-cell sensitivity in mV/V, capacity in kg, dead load in kg. Validate with the live weight readout.
3. Calibrate scale: DR1 → zero with empty feeder, span with calibrated test weight. Siwatool computes the calibration factor and writes it to the module's EEPROM.
4. Configure dosing: DR6 → set refill mode (manual / automatic), refill threshold, dosing tolerance band, refill hysteresis. These parameters only appear under Siwatool FTC_L.
5. Configure feeder actuator control: DR7..DR10 → set screw/vibratory drive response curve, dosing integrator time constant, refill dwell time.
6. Configure filter: DR5 → select low-pass cutoff (typically 1..5 Hz for loss-in-weight feeders with screw drives, 0.1..1 Hz for vibratory feeders).
7. Verify totals: trigger a manual dose and confirm the integrated weight loss matches the metered reference within the configured tolerance.

Troubleshooting Matrix

Verification After Software Change

After any Siwatool edition switch or version upgrade, perform this verification sequence before returning the system to production:

1. Read DR0; confirm Application matches the physical scale type and Firmware version is the expected release.
2. Read DR1; confirm zero and span match the exported baseline within ±0.05 %.
3. Read DR6 (loss-in-weight systems); confirm refill mode, threshold, and tolerance are non-default.
4. Trigger a manual refill cycle; observe DR7..DR10 live values to confirm the feeder control responds.
5. Trigger a manual dose; compare integrated weight loss against the reference feeder.
6. Cycle module power; reconnect Siwatool and re-read DR6 to confirm parameters survived the power cycle (i.e., they were committed to EEPROM, not held in RAM).

Field-Proven Caveats

• Siwatool FTC_L licenses are tied to one PC. Keep a second licensed backup laptop for hot-swap situations.
• Always export the DR table before any firmware change. The "Load Defaults" button inside Siwatool wipes calibration and dosing parameters without further confirmation.
• If the host PC's Windows user account does not have administrator rights, Siwatool's COM service fails silently. Run the installer as administrator and launch Siwatool as administrator for the first connection.
• Do not attempt to load belt-scale firmware into an FTC module currently controlling an active loss-in-weight feeder. Stop dosing, empty the hopper, and isolate the feeder actuator before any firmware swap.
• Siwatool version (V2.1.9, V2.3.1, etc.) is independent of the FTC_B / FTC_L edition. A V2.3.1 FTC_B install is still missing DR6.

FAQ