Troubleshooting Emidate ET200M Analog 22.96 mA Overflow Migration

Problem Description

An Emidate runtime station equipped with a Siemens CP5613 Profibus master card is connected to two SIMATIC ET200U distributed I/O stations. The legacy ET200U head stations and their S5-style signal modules have reached end-of-life and can no longer be procured. The plant is replacing the ET200U head modules and analog signal modules with SIMATIC ET200M (IM 153-x) carrying SM 331 / SM 332 signal modules. The Emidate project is preserved; only the I/O module type is changed inside the Emidate parameter editor from the ET200U type to the S7 module type.

After reconfiguration and bus restart, the following symptoms appear:

• Digital input values are read and displayed correctly in Emidate.
• Analog input values are stuck at 22.96 mA with status flag O (overrange) on every analog channel of every ET200M station.
• No diagnostic, station failure, or Profibus error is reported in the Emidate diagnostic window, in the CP5613 diagnostics, or in the Windows device manager.
• The same physical 4-20 mA field transmitters are unchanged; only the terminal wiring has been moved from the ET200U terminals to the ET200M terminals.
• The analog signal cable shields, the 24 V field-side supply, and the transmitter loop power are intact (verified with a hand-held mA calibrator).

The fault is reproducible on every analog channel of every ET200M station. The previous installation with the original ET200U modules read the same transmitters well below 22.96 mA with no overrange flag, so the field signal and the transmitters themselves are exonerated. The fault is therefore inside the Emidate-side periphery description, not in the loop wiring.

System Architecture

The PC station runs the Emidate emission-data-acquisition application as the Profibus DP class-1 master. The CP5613 (Siemens order number 6GK1561-3AA00) provides the Profibus DP interface and is supervised by the SIMATIC NET PC software stack. Two DP-1 slaves (ET200U before migration, ET200M after migration) terminate the segment. The bus topology is daisy-chain Profibus cable with terminating resistors enabled only at the physical ends of the segment. A typical reference layout is shown below.

Emidate stores the project database inside its own proprietary repository. Each analog channel has a "periphery type" attribute that is used by the Emidate runtime to interpret the raw word coming back from the DP slave. When the slave is an ET200U carrying S5 signal modules, Emidate expects an S5 raw layout and an S5 measurement-range coding. When the slave is an ET200M carrying SM 331 modules, Emidate expects an S7 raw layout and an S7 measurement-range coding. Simply changing the Emidate module-type selector from "ET200U" to "S7 module" does not by itself update the per-channel periphery type. The per-channel setting must be revisited and explicitly set to the S7 analog type, otherwise Emidate applies the S5 scaling rules to S7 raw values.

Root Cause Analysis

The 22.96 mA value is the canonical upper end of the Siemens 4-20 mA input overrange for the SM 331 AI modules configured for current measurement. When the raw value that the master reads out of the slave is interpreted with the wrong range, the calculated engineering value collapses to the upper end of the range that Emidate believes is valid. The status flag O in Emidate is the overrange / overflow bit inherited from the S7 status byte. The S7 status byte bit 2 ("overflow") and bit 1 ("overrange") are propagated by Emidate and surfaced as the single-character flag O.

Two independent configuration layers have to agree for the analog channel to read correctly:

1. Hardware layer (SM 331 / ET200M side): the measuring-range module on the SM 331 must be mechanically set to the "D" or "C" position that corresponds to 4-wire 4-20 mA, and the same range must be selected in the STEP 7 / HW Config property dialog of the AI channel.
2. Application layer (Emidate side): the Emidate parameter record for that channel must declare the periphery type as S7: AE 4..20 mA (German UI) or its localized equivalent (for example S7: AI 4..20 mA in the English UI). The default that Emidate inherits from a previous ET200U configuration is the S5 type, even after the module-type selector at project level has been switched to "S7 module".

When layer 2 still holds the S5 type, Emidate applies S5 scaling rules to an S7 raw word. Because S5 and S7 number formats, sign conventions, and end-of-overrange scaling differ, the result saturates at the S7 overrange ceiling of 22.96 mA and the overrange flag is asserted, regardless of the actual loop current. The symptom is therefore not a wiring fault, not a transmitter fault, and not a Profibus fault: it is a pure parameter-mapping fault inside the Emidate project.

Solution 1: Emidate Periphery Type Configuration

Apply the per-channel periphery-type correction in Emidate. The change is required on every analog channel, not just one. Plan the change for a maintenance window because the Emidate runtime must be restarted for the new periphery description to be loaded.

1. Open the Emidate project in the Emidate configuration tool (also called the Emidate engineering client).
2. Navigate to Project > I/O > Analog channels (the exact menu path is version-dependent; on V6.0 it is Project > Parameter > Periphery).
3. For each analog channel assigned to an ET200M station, open the channel properties.
4. On the Periphery type drop-down, change the selection from the legacy S5 / ET200U type to S7: AE 4..20 mA (or the localized equivalent that includes "4..20 mA" and "S7").
5. Confirm the engineering range displayed in the dialog matches the actual physical range of the transmitter (typically 0 .. 100 % mapped onto 4 .. 20 mA).
6. Save the project, then restart the Emidate runtime service.

If the drop-down only lists S5 types, the project still has an S5 module class at the station level. Verify that the station's module-type selector has been switched to S7 module and that the Emidate V6.0 (or later) build is being used. Earlier Emidate builds that pre-date S7 do not expose the S7 periphery types and cannot be parameter-corrected; they have to be migrated (see "Emidate V6.0 Capability Assessment" below).

Solution 2: CP5613 Profibus Master Configuration via NCM-Manager

The Emidate runtime requires the CP5613 to be configured as a Profibus DP class-1 master that owns a known set of slaves. The configuration is stored in the PC station's database and consumed by the SIMATIC NET runtime. Two configuration tools have shipped over the lifetime of the CP5613:

• NCM-Manager (also called NCM S7 Manager / NCM PC) for projects based on STEP 7 V5.x. The configuration is built as a PC station with a CP5613 in slot 1 and the DP slaves attached under the master interface.
• COM Profibus for legacy projects that pre-date NCM. COM Profibus is no longer maintained and is recommended only when an existing master database has to be re-loaded.

On Emidate V6.0 with a current SIMATIC NET stack, NCM-Manager inside STEP 7 V5.5 (or the equivalent PC-station editor in TIA Portal for newer stacks) is the correct tool. The configuration procedure is:

1. Open STEP 7 V5.5 and the PC station that owns the CP5613.
2. In SIMATIC PC Station > Configuration, verify that the CP5613 is in slot 1 with index 0 (or the index that matches the CP5613's physical order number).
3. Open the CP5613 properties, set the operating mode to DP master, and assign a Profibus address that does not collide with the two ET200 stations (typical: master = 1, slaves = 3 and 4).
4. Insert the two ET200M stations under the CP5613 master interface and assign the matching Profibus addresses.
5. Load the GSD file for the IM 153 head module if it is not already in the STEP 7 hardware catalog.
6. Compile and download the PC station. Confirm the CP5613 LED transitions from "STOP" to "RUN" and that the bus scan in NCM-Manager reports both ET200M stations as OK.
7. Restart the Emidate runtime service so that it binds to the freshly loaded master database.

Emidate V6.0 Capability Assessment

Emidate V6.0 from the Siemens emission-data product line supports both S5-style modules (the legacy ET200U analog modules) and S7-style modules (the modern ET200M analog modules), as documented in the official Emidate product flyer. The application is described as a complete system that collects, monitors, evaluates, and stores all emission-related values and plant states. For migration projects, the relevant facts are:

• S7 periphery types for SM 331 / SM 332 channels are present in the V6.0 drop-down lists.
• The project-level module-type selector exposes an S7 module choice that does not exist in pre-V6.0 builds.
• The HMI / display layer treats S7 and S5 values identically after the periphery type is set, so historical trend files do not have to be re-baselined.
• Licensing is per channel and is portable across module families; migrating from S5 to S7 does not require additional channel licences.

The flyer explicitly positions Emidate as a complete system offering, which is the practical justification for migrating in place rather than replacing the application. A pre-V6.0 Emidate project that has no S7 periphery type in the drop-down cannot be patched into compatibility by editing the project; the project must be opened and saved with a V6.0 (or later) build before the S7 module types become selectable. The Emidate V6.0 build, in combination with the NCM-Manager re-configuration of the CP5613, is therefore the canonical migration path.

ET200U vs ET200M Module Selection

The migration must preserve the original signal range and channel count. The table below summarizes the typical one-to-one replacements that work with Emidate and the CP5613.

Wiring and Signal Conditioning

The migration re-uses the existing 4-20 mA loop wiring, but the terminal layout changes because the ET200M terminal block is mechanically different from the ET200U terminal block. Verify the following wiring rules on every analog channel before commissioning the new ET200M station:

1. The transmitter positive terminal lands on the SM 331 channel input (for example terminal 2 for channel 0 of a 6ES7 331-7KF02-0AB0). The transmitter negative terminal returns to the SM 331 channel ground (for example terminal 3).
2. If the transmitter is a 2-wire device, the 24 V loop supply must be sourced from the SM 331 sensor supply (terminal 1 and terminal 5 on the typical SM 331 AI 8) or from an external 24 V rail. Verify the loop voltage at the transmitter terminals with a multimeter; a typical 2-wire 4-20 mA transmitter needs at least 12 V to operate.
3. If the transmitter is a 4-wire device, the loop is powered from an external 24 V supply and the signal wires only carry the mA current back to the SM 331 input.
4. The shield of the analog cable must be landed at the EMC bar of the ET200M head module and grounded at one end only.
5. Verify that the unused analog input channels are configured as "deactivated" in HW Config so they do not contribute noise or pull-up currents into the active channels.

The loop current can be sanity-checked with a hand-held mA calibrator inserted in series with the channel. A reading inside 4 .. 20 mA on the calibrator while Emidate still reports 22.96 mA / flag O confirms that the field wiring and the transmitter are correct and that the remaining fault is purely a parameter-mapping issue inside Emidate.

Verification Procedure

Run the following checks in order after the parameter change and the PC-station download. Treat each step as a gate; do not move on if the gate fails.

1. Open the CP5613 diagnostics in NCM-Manager (or in the SIMATIC NET configuration tool). Confirm both ET200M stations are listed as OK and that no slave reports Station failure or Diagnostic not OK.
2. Open the ET200M station's online diagnostics in STEP 7 HW Config. Confirm every SM 331 channel is in the OK state and that no channel reports Wire break, Short circuit, or Overrange.
3. Open the Emidate runtime and navigate to the analog channel list. Confirm that the overrange flag O has cleared and that the displayed engineering value tracks the actual loop current.
4. Inject three known currents (for example 4 mA, 12 mA, 20 mA) using a calibrator and verify the displayed engineering values. The error band should be inside the accuracy class of the SM 331 module used (typical: ±0.3 % of full scale for the 13-bit module, ±0.1 % for the 16-bit module).
5. Force the calibrator above 20 mA (for example 22.5 mA) and confirm that Emidate displays the overrange flag O and an engineering value at or just below the S7 overrange ceiling of 22.96 mA. This proves that the overrange path is still functional after the parameter change.
6. Force the calibrator below 4 mA (for example 3.5 mA) and confirm that Emidate displays the underrange flag U and an engineering value at or just above the S7 underrange floor of 1.19 mA. This proves that the underrange path is also still functional.
7. Sign off the channel list with the calibrator measurements and archive the Emidate project.

Troubleshooting Matrix

Preventive Recommendations

• Document the per-channel periphery type in a project parameter sheet alongside the loop drawing. The sheet must list the Emidate channel ID, the SM 331 slot/channel, the transmitter tag, and the periphery type. This makes the next migration a one-page exercise instead of a forensic investigation.
• Keep the PC-station database in version control (for example in a STEP 7 V5.5 project archive on a managed share) so that the CP5613 master configuration is reproducible after a hardware swap.
• Maintain a small bench rig with one ET200M station, one SM 331 module, and a mA calibrator. Reproduce every periphery-type setting on the bench before applying it to the live station. The bench rig is the cheapest insurance against a recurrence of the 22.96 mA / O symptom.
• When Emidate is upgraded across a major version, re-validate every analog channel end-to-end. New builds occasionally re-map S7 status bits to the Emidate flag set, which can change the meaning of O and U.
• Schedule the next expected ET200U phase-out in the plant's obsolescence register. The ET200U family is no longer orderable, so a structured migration plan removes the fire-fighting mode that produces symptoms of this type.

FAQ