Macro 19 uses an enable/stop input and separate clockwise and counterclockwise start commands. Macro 20 uses enable/stop, a start command and a direction selection. The drive handles the three-wire run state; a normal stop input is not a safety circuit.
Choose the pushbutton arrangement
Three-wire operation suits a local panel where a brief press starts an operating sequence and a separate stop control ends it. Decide whether the operator should press separate direction-start buttons or select a direction and then press Start. Those are different control arrangements and should have different panel labels.
| Referenced CU240E-2 input | Macro 19 | Macro 20 |
|---|---|---|
| DI0 | Enable / OFF1 | Enable / OFF1 |
| DI1 | Start clockwise | Start |
| DI2 | Start counterclockwise | Reversing selection |
| DI3 | Fault acknowledgement | Fault acknowledgement |
| AI0 | Speed reference | Speed reference |
This mapping follows the cited Siemens presets. Check the available macro and actual connections for the control unit and firmware installed. Notice that fault acknowledgement moves to DI3 compared with the two-wire preset. A reused panel drawing can otherwise connect a reset button to a direction-related command.
Understand stop-enable and start signals
The operating enable is normally maintained in its permissive state. A stop action removes that permission and requests OFF1. For a conventional positive-logic panel, a normally closed stop contact is often used so pressing it removes the signal; confirm the complete input polarity and wiring design before adopting that arrangement.
A momentary start is meaningful only with the appropriate permission and sequence. Keep the start contact released before testing another start. Simply restoring a permissive should not be treated as the operator’s deliberate start action in the acceptance procedure.
For macro 20, the reversing input is a direction selection, not a second start button. For macro 19, each direction has its own start command. Consult the exact timing diagram for requests made during motion, conflicting inputs and permission restoration.
Commission the panel in stages
- Back up the online drive and document the existing input assignments. Identify the required stop and restart behavior before selecting a macro.
- Isolate power and follow the equipment discharge procedure before wiring. Retain the designed safety circuit; do not bridge a safety input to make the lab run.
- Select macro 19 or 20 only if supported by the installed control unit. Inspect the command source, reference path and input mapping afterward.
- With motion prevented, monitor r0722. Operate Stop, each Start or direction selector, and Reset individually. Confirm every label matches the observed input.
- Use an approved low speed reference and a controlled test area. Verify one start/stop cycle before testing another direction.
- Save the verified configuration to nonvolatile memory, upload a dated copy and attach the final terminal schedule.
Do not add a separate self-holding PLC bit merely because a traditional contactor circuit used one. First understand whether the selected drive function already provides the intended state handling. Unnecessary latching can make the stop and restart sequence harder to diagnose.
Practical lab: verify a complete operating cycle
| Test | Record |
|---|---|
| Enable absent; momentary start operated | Input states and resulting drive state |
| Enable present; valid fresh start | Start transition and requested direction |
| Start button released | Continued run behavior under the selected function |
| Stop pressed while running | OFF1 request and observed deceleration |
| Stop released without another start | Whether the installation remains in its required stopped state |
| Controlled fault recovery or power restoration | Required acknowledgement and fresh-start procedure |
Carry out the last test only under the approved commissioning procedure. It should establish what the whole installation does after interruption, including PLC outputs and external relays. The drive macro alone cannot describe all of those behaviors.
For a direction selector panel, start with the direction selected while stopped. If direction changes during motion are permitted by the application, test that case separately and record the response. Do not infer dynamic behavior from a successful start in each direction.
The lab record should show the operator action, observed signal transition, expected state and actual result. Resolve any difference before returning the equipment to production.
Diagnose common three-wire control faults
| Problem | Inspect |
|---|---|
| Start has no effect | Enable input, start transition, active data set and drive state |
| Reset changes direction | DI2/DI3 assignment left over from a different macro |
| Run exists only while button is held | Actual command routing may still be two-wire |
| Stop release causes unexpected behavior | Stuck start input, external latch, restart logic and timing sequence |
| Motor is enabled but has no speed | Analogue reference, scaling and setpoint path |
Separate input wiring faults from logic faults by checking raw input state first. A correct input bit with the wrong drive response points toward mapping, active data set or sequence conditions. A bit that does not follow the button points toward the electrical path.
Continue with two-wire control comparison or analogue reference commissioning when reviewing the panel design.
Frequently asked questions
What is the main difference between macros 19 and 20?
Macro 19 has separate clockwise and counterclockwise start commands. Macro 20 has one start command and a separate reversing selection, alongside the enable/stop input.
Is the normally closed stop button an emergency stop?
Not by itself. This guide describes operational OFF1 control. Emergency stopping and other safety functions require the machine’s validated safety design.
Why did the fault-reset input change?
In the referenced three-wire presets, DI2 is a control command and DI3 acknowledges faults. Check the new mapping whenever changing from a two-wire preset.
Technical references
Use the document edition matching your installed hardware and firmware. The linked manuals establish the device-specific facts; the worked examples and check sheets are training exercises.