FSoE and TwinSAFE

Scope

ecmccfg can map and cyclically forward Fail Safe over EtherCAT (FSoE) telegrams between TwinSAFE devices. The safety application itself must be configured and downloaded with TwinCAT or TwinSAFE Loader.

Direct cyclic forwarding

The generic configuration uses Cfg.EcAddEntryCyclicWrite(<to>,<from>) instead of an ecmc PLC expression. Both EtherCAT entries must exist before the link command runs, and all connections must be configured before Cfg.SetAppMode(1).

For a MO1918 safety master with two MO7221 safety slaves, first add the master and its two directly mapped connections:

${SCRIPTEXEC} ${ecmccfg_DIR}addSlave.cmd, "SLAVE_ID=4,HW_DESC=MO1918-0000"
${SCRIPTEXEC} ${ecmccfg_DIR}addFSoEConn.cmd, "SFTY_MASTER_SID=4,SFTY_MASTER_CONN=01"
${SCRIPTEXEC} ${ecmccfg_DIR}addFSoEConn.cmd, "SFTY_MASTER_SID=4,SFTY_MASTER_CONN=02"
${SCRIPTEXEC} ${ecmccfg_DIR}finishFSoEMaster.cmd, "SFTY_MASTER_SID=4"

Add the safety slaves and their normal hardware configurations, then link the endpoints:

${SCRIPTEXEC} ${ecmccfg_DIR}addSlave.cmd, "SLAVE_ID=8,HW_DESC=MO7221-9016-1114"
${SCRIPTEXEC} ${ecmccfg_DIR}addSlave.cmd, "SLAVE_ID=9,HW_DESC=MO7221-9016-1124"

${SCRIPTEXEC} ${ecmccfg_DIR}linkFSoEConn.cmd, "SFTY_MASTER_SID=4,SFTY_MASTER_CONN=01,SFTY_SLAVE_SID=8,SFTY_SLAVE_CONN=01"
${SCRIPTEXEC} ${ecmccfg_DIR}linkFSoEConn.cmd, "SFTY_MASTER_SID=4,SFTY_MASTER_CONN=02,SFTY_SLAVE_SID=9,SFTY_SLAVE_CONN=01"

ECMC_EC_MASTER_ID selects the EtherCAT master automatically. The connection numbers are written as two hexadecimal digits because they are also used in the EtherCAT entry names.

The required call order is:

1. Add the safety master.
2. Add every master-side FSoE connection.
3. Finish the safety-master mapping with finishFSoEMaster.cmd. This appends its standard-output, EFUSE, and device-status PDOs after the FSoE telegrams.
4. Add the safety slaves, including their FSoE PDO mappings.
5. Link each master connection to its slave connection.
6. Activate application mode.

finishFSoEMaster.cmd is required for safety masters whose fixed PDOs follow the project-dependent FSoE connections. It must run exactly once, after the last addFSoEConn.cmd call. For the MO1918 this produces the process-image order reported by the slave:

SM2: 0x1600, 0x1601, ..., 0x17f0, 0x17ff
SM3: 0x1a00, 0x1a01, ..., 0x1bfe, 0x1bff

The ellipsis represents additional configured FSoE connections. The standard outputs and the EFUSE/device-status PDOs must remain after them. Adding those fixed PDOs in addSlave.cmd, before the dynamic connections, gives ecmc a different process-image order and shifts the FSoE data even though EcPrintSlaveConfig() prints the expected PDO indices.

Telegram mapping

The six-byte telegram is registered directly as four packed entries rather than as one unsupported 48-bit datatype:

Mandatory bit groups and gaps that occupy a complete byte are registered as packed U8 entries. This avoids invalid B1/gap combinations while preserving the exact PDO length expected by the slave.

The connection ID is mapped directly as the final U16 entry in each telegram. An additional Cfg.EcAddDataDT() view is not needed when the PDOs are registered in process-image order. EcAddDataDT() is still useful for named bit views, such as the MO1918 Reset and Run controls inside its packed standard-output byte.

MO1918 diagnostics

The MO1918 hardware panel provides controls for the standard outputs and links to both the FSoE overview and an expert panel.

EFU-Stat uses the standard Beckhoff MX layout:

The current entry is EtherCAT object 0x6040:18 with datatype REAL, mapped as F32 and exposed to EPICS through asynFloat64.

Hardware-panel navigation

The normal hardware-panel path is used:

ecmcMain.ui
  -> generic EtherCAT slave overview
  -> ecmcMO1918-0000.ui
  -> FSoE connections
  -> generated FSoE connection overview

The MO1918 hardware definition sets PnlTyp to MO1918-0000. Its FSoE button opens ecmcFSoEMaster.ui, which contains reusable ecmcFSoEConnRow.ui rows for connections 01 through 08. Each row is visible only when its RmtSID metadata PV exists and contains a positive slave ID. This supports up to eight configured connections without a launcher script or generated UI. Each visible row can open the connection details or the connected safety-slave hardware panel.

linkFSoEConn.cmd loads navigation metadata such as:

$(IOC):FSoE-M1-CH01-RmtSID
$(IOC):FSoE-M1-CH01-RmtConn
$(IOC):FSoE-M1-CH02-RmtSID
$(IOC):FSoE-M1-CH02-RmtConn

The Open slave buttons call ecmcOpenObject.sh EC_SLAVE_GENERIC. That helper reads the remote SID PV, resolves the remote device’s PnlTyp, and opens its standard hardware panel. The MO7221 hardware panel also provides a direct FSoE details button for its connection 01.

The compact navigation metadata currently assumes one safety master per EtherCAT master. This does not affect telegram forwarding; it only affects the names used for panel navigation.

Diagnostics

If Cfg.EcAddEntryCyclicWrite(...) returns ERROR_MAIN_EC_ENTRY_NULL (0x20014), at least one named endpoint was not created. Check that addFSoEConn.cmd ran for the master connection and that the safety-slave FSoE mapping was loaded before linkFSoEConn.cmd.

An EtherCAT AL status of 0x0025 (Invalid Output Mapping) normally means the configured PDO order, entry sizes, or total SyncManager length differs from the mapping expected by the device. Compare the configuration with an export for the exact product code and revision.

Rapidly changing or implausible connection IDs are another indication of a process-image offset error. For example, an MO1918 connection ID showing the EFUSE status value, or the Safe Logic state/cycle counter, means the trailing PDOs were registered before the FSoE connections. Verify that finishFSoEMaster.cmd ran after every addFSoEConn.cmd and before Cfg.SetAppMode(1).

Useful runtime checks are:

ethercat pdos -m <master> -p <slave> -v
ecmcConfig "EcPrintSlaveConfig(<slave>)"

The EtherCAT output establishes the physical PDO layout. The ecmc output confirms which entries and sizes were registered; live EPICS monitoring can then reveal an offset mismatch.

If an MO7221 reaches Ready to switch on (0x0021) but does not advance when the controlword changes to 7 or 15, verify its stored operating mode:

ethercat upload -m <master> -p <slave> -t int8 0x7010 3

The standard ecmccfg MO7221 mapping uses cyclic synchronous velocity mode (CSV), so the value must be 9. A device previously configured by TwinCAT may retain CSP mode (8). The MO7221 hardware configuration explicitly writes CSV during PREOP and registers the setting for reapplication after reconnect.

MO7221 is also available with cyclic synchronous position mode descriptors:

MO7221-9016-1114_CSP  # 24 V
MO7221-9016-1124_CSP  # 48 V

These select mode 8 and map target position through PDO 0x1611, object 0x7010:05, as positionSetpoint01. The CSP RxPDO assignment contains 0x1610 and 0x1611; it does not include the CSV torque-offset PDO. The descriptors without _CSP select mode 9 and map target velocity through 0x1612, object 0x7010:06.

The CSP descriptors set PnlTyp to MO7221-9016_CSP. Its hardware panel retains the normal MO7221 status and FSoE navigation, while its Expert button opens the CSP drive panel with position-command PVs instead of CSV velocity commands.

Related pages

• Advanced EtherCAT and Commissioning
• Beckhoff MX-System
• Panels