The transfer request starts at the control’s I/O function, passes through the serial interface and cable, and ends at the PC’s communications software. Follow the packet. If the control raises 570 no dnc option when DNC is selected, execution stops at the control’s option check—before cable wiring, serial framing, or PC software can affect the result.
Where does the DNC request stop?
The control displays a catalog of functions on the page reached through MNT and version. A listed name identifies a function that the control family can support. Highlighting identifies an installed function on this machine. Here, only EIA is highlighted; dnc is merely listed.
| Observation | Meaning | Commissioning decision |
|---|---|---|
EIA is highlighted |
EIA program handling is installed | Commission EIA transfer through the control’s tape I/O functions |
dnc is listed but not highlighted |
DNC is available for the control family but is not activated on this machine | Do not troubleshoot the RS-232 cable as a remedy for alarm 570
|
570 no dnc option appears |
The selected operation requires the uninstalled DNC function | Select a licensed I/O path or obtain the option through the manufacturer |
DNC and ordinary EIA file transfer are separate capabilities. DNC commonly means executing or feeding program data through an external path, while tape I/O transfers a program between control memory and an external device. An installed EIA function can therefore support tape-style input and punch output without licensing the separate DNC execution mode.
Check: Return to the option page and verify whether dnc itself is highlighted. If it is not, alarm 570 is an option-state result, not a serial-link diagnostic.
What do the other option names prove?
Read each line as a feature-family label, not as proof of installation. The option page contains EIA, dnc, spiral, EIA 3-D comp, rotation, geometric, scaling, EXT-data I/O, MEM 76m, and FLX print. Highlight state remains the deciding indication.
| Displayed label | Engineering interpretation | What must be checked |
|---|---|---|
EIA 3-D comp |
A three-dimensional compensation feature associated with EIA operation | Use the option or programming manual for the exact compensation data, axes, and syntax |
geometric |
A geometric-processing option family; the short screen label does not define its operations | Match the label to the control-specific option description before planning a process around it |
EXT-data I/O |
An external-data input/output feature family | Do not equate it automatically with DNC or basic RS-232 tape transfer; check its control-specific interface description |
The same rule applies to every entry: a feature name can appear in system software even when its activation is absent. Machine configuration, not presence in the catalog, decides whether the function can be invoked.
Check: Record the highlighted entries separately from the complete list. Use only the highlighted list when determining which operating modes are available.
How do you prove the RS-232 physical path?
Layer one first. After choosing tape I/O rather than DNC, the path is control serial transmitter, connector, cable conductors, PC serial receiver, and communications application. A moving cursor during punch all proves that the control is processing its program list. It does not prove that voltage transitions reached the connector or that the PC received characters.
- Identify the control’s single RS-232 connector and the PC-side interface actually used, including any serial adapter.
- Obtain the required connector pin assignment from the machine documentation. Compare it conductor by conductor with the cable; do not infer straight-through or crossed wiring from connector shape.
- Check continuity for transmit, receive, signal common, and any configured handshake conductors. Check for shorts between adjacent pins.
- Inspect the connector for bent pins, loose backshell wiring, corrosion, and an adapter that enumerates on the PC but is connected to a different application port.
- Start the PC software’s receive or debug display before commanding a punch from the control.
The adjacent on/off switch must not be treated as an EIA-mode selector from its location alone. It may control a nearby outlet. Read the panel legend or electrical drawing before operating it; serial transfer selection belongs in the I/O function unless the machine documentation explicitly assigns the switch another role.
Check: During a punch, the PC should receive characters or at least framing-error data. Receiving nothing directs attention to port selection, cable pinout, handshake state, connector hardware, or the control’s serial parameters.
Which serial settings must match?
Once electrical continuity is correct, compare both endpoints. RS-232 has no network address, so the selected physical PC port is the effective destination. Baud rate and character framing must match exactly. Flow-control configuration must also agree with the cable conductors and control parameters.
| Setting | Control side | PC side | Failure signature |
|---|---|---|---|
| Port | Installed RS-232 interface selected by tape I/O | Operating-system port assigned to the cable or adapter | No characters when the wrong PC port is open |
| Baud rate | Read the tape-reader or punch parameter | Enter the same rate | Unreadable or framing-error characters |
| Data bits, parity, stop bits | Read all framing parameters | Match each field | Corrupt characters, parity errors, or rejected records |
| Flow control | Read the configured software or hardware handshake mode | Select the corresponding mode | Transfer never starts, stops early, or pauses indefinitely |
| Program framing | Use the control’s required tape format | Configure start/end characters and line termination accordingly | Characters arrive, but the control does not create a valid program |
Settings handwritten beside the tape-reader parameters are commissioning clues, not final values. Read the live parameters from the control and transcribe them exactly. Do not change several fields simultaneously; one-at-a-time changes preserve the diagnostic trail.
Check: Punch one short program and confirm that the PC receives readable program text without framing or parity errors.
How should tape I/O be commissioned?
- On the PC, select the verified serial port and enter the framing and flow-control values read from the control.
- Open the receive/debug window before sending from the machine.
- At the control, select tape I/O and punch one small EIA program. Avoid
punch alluntil the link is stable. - If the PC receives nothing, return to the physical path and handshake checks. If it receives corrupt data, correct baud rate or framing. If readable data stops partway through, examine flow control and cable conductors.
- After output works, reverse the direction. Put the control in its tape-input state, transmit one known EIA program from the PC, and check that the control accepts it into memory without invoking DNC.
Tape I/O is the correct licensed path for ordinary EIA program exchange in this configuration. It does not remove the memory and syntax constraints of the control, and it does not activate continuous DNC operation.
Check: Confirm one complete program in each direction before transferring the full program set.
What proves the complete path works?
Verify the link at each boundary: the selected control function starts, serial characters leave the control, the PC receives readable records, the reverse transfer reaches the control, and the received program is accepted as an EIA program. Alarm 570 should not appear because the test does not select DNC.
Use a known short program with an identifiable program number. Punch it to the PC, inspect its beginning, line structure, and ending, then transmit it back under a different permitted program number if the control requires uniqueness. Open the received program at the control and perform the control’s normal program validation before any execution.
Check: The final acceptance condition is a readable PC capture followed by a complete tape-input transfer that creates a valid program in control memory.
FAQ
What happens if DNC is listed but not highlighted?
The control family recognizes the DNC feature name, but this machine does not have it activated. Selecting that function produces 570 no dnc option.
What happens if punch all shows progress but the PC receives nothing?
The cursor proves internal punch processing only. Check the selected PC port, cable pinout, transmit and signal-common conductors, handshake wiring, and live serial parameters.
What happens if the PC receives unreadable characters?
Compare baud rate, data bits, parity, and stop bits at both endpoints. Correct one mismatch at a time and repeat the short-program punch.
What happens if tape output works but input fails?
Verify the reverse signal path, the control’s tape-input state, program framing, flow control, and program-number acceptance. Finish by receiving one known EIA program into control memory and validating it at the control.