S-Err Sequence Error / Input Conflict fault in Toshiba drive
S-Err Sequence Error / Input Conflict fault in Toshiba drive
Description "S-Err" is a logic state fault rather than a hardware failure. It occurs when the drive receives conflicting operational commands simultaneously. The most common scenario is receiving a "Run Forward" (F) command and a "Run Reverse" (R) command at the exact same time. The drive logic cannot determine which direction to turn, so it declares a Sequence Error and refuses to start (or stops if already running) to prevent mechanical damage or oscillation. Causes
1. PLC Programming: The external PLC logic is flawed, keeping the Forward bit high while triggering the Reverse bit.
2. Switch Failure: A 3-position selector switch (Hand-Off-Auto) has a shorted contact block, bridging FWD and REV terminals.
3. Wiring Cross: Moisture in the conduit is creating a bridge between the F and R terminal wires.
4. Parameter Setup: Logic inputs are assigned incorrectly (e.g., S1 is assigned "Forward" while F is also "Forward"). Solution Check the Input Terminal Status on the keypad monitor. You will likely see both "F" and "R" highlighted/active.
Disconnect the field wiring from terminals F and R. If the S-Err clears, the issue is external (bad switch or shorted wire). If S-Err persists with wires removed, check your parameter assignments (F110-F118). Ensure no two terminals conflict.
If you require an application where both inputs might be high (e.g., a "Priority" system), change the "Input Logic" parameters to prioritize one over the other (Last Signal Priority vs First Signal Priority), although resolving the physical wiring conflict is the safest approach.
Description "S-Err" is a logic state fault rather than a hardware failure. It occurs when the drive receives conflicting operational commands simultaneously. The most common scenario is receiving a "Run Forward" (F) command and a "Run Reverse" (R) command at the exact same time. The drive logic cannot determine which direction to turn, so it declares a Sequence Error and refuses to start (or stops if already running) to prevent mechanical damage or oscillation. Causes
1. PLC Programming: The external PLC logic is flawed, keeping the Forward bit high while triggering the Reverse bit.
2. Switch Failure: A 3-position selector switch (Hand-Off-Auto) has a shorted contact block, bridging FWD and REV terminals.
3. Wiring Cross: Moisture in the conduit is creating a bridge between the F and R terminal wires.
4. Parameter Setup: Logic inputs are assigned incorrectly (e.g., S1 is assigned "Forward" while F is also "Forward"). Solution Check the Input Terminal Status on the keypad monitor. You will likely see both "F" and "R" highlighted/active.
Disconnect the field wiring from terminals F and R. If the S-Err clears, the issue is external (bad switch or shorted wire). If S-Err persists with wires removed, check your parameter assignments (F110-F118). Ensure no two terminals conflict.
If you require an application where both inputs might be high (e.g., a "Priority" system), change the "Input Logic" parameters to prioritize one over the other (Last Signal Priority vs First Signal Priority), although resolving the physical wiring conflict is the safest approach.
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