Serial Port

Use the following dialog to configure basic serial port settings. The serial port settings must match those selected on the CNC. Please refer to the CNC manual for further information.

Serial port settings

COM Port

Select the serial port that is connected to CNC from this list.

In some cases, not all the ports installed on the server are shown. This happens if the port is not installed correctly, or if the port could not be detected. Please refer to [LINK:trouble_port_not_detected] for information on how to use such ports.

Baud rate

Select the baud rate from this list.

The baud rate is the transmission speed, in bits per second. The speed must match that of the CNC.

Stop bits

Number of bits appended after each character to indicate the end of a character. The number of stop bits must match the number of stop bits selected on the CNC.

Data bits

Number of bits in each character. The number of data bits must match the number of data bits selected on the CNC.

Parity

Parity is a mechanism used for error checking. The parity setting must match the parity setting on the CNC.

None: No error checking is performed.
Even: An extra bit is sent at the end of each character. If the character contained an even number of '1' bits (mark bits), the parity bit is '0'. If the character contained an odd number of '1' bits, the parity bit is '1'. The result is that there is always an Even number of mark bits in the character.
If there was a transmission error, and a single bit was sent as '0', but received as '1', then the parity would not match, so the receiving system would know that this character had an error.
Odd: The opposite of Even, the parity bit is set so the character contains an odd number of '1' bits.
Mark: The parity bit is always '1'. Errors will not be detected when Mark parity is selected.
Space: The parity bit is always '0'. Errors will not be detected when Space parity is selected.

Port Mode

Select the type of port from this list.

When EIA mode is selected, you should also select just a single \LF character as the 'Linefeed Type' on the 'Transmit' setup sheet.

Flow control settings

Flow control is used when the CNC cannot process the received data fast enough. To prevent the CNC input buffer from overflowing, it signals the DNC server, that is should temporarily suspend the transmission.

The method of exchanging signals for data flow control between the DNC and the CNC is called handshaking. There are two basic methods: Software (XOn/XOff) and Hardware handshaking.

Flow control

Select the type of flow control from this list.

Software handshaking

Two bytes, not normally used during text transmissions, are assigned to pause (XOff) and restart (XOn) the transmission.

Whenever the CNC wants to interrupt the data flow from the DNC, it sends an XOff (Transmission Off). When its buffers have been purged, it sends an XOn (Transmission On) to signal that it is ready to receive data again.

XOn/XOff is limited to text transmission. It cannot be used with binary data, since binary files can contain the XOn and/or XOff character.

Hardware handshaking

The corresponding handshake signals are sent over different wires. The main problem is, that an extra investment is needed since extra lines are necessary in the communication cable to carry the handshaking information.

The hardware handshake type needs to be selected from the Hardware flow type drop-down list.

It is possible to use both software and hardware handshaking at the same time.

The flow control setting must match the flow control setting on the CNC.

Hardware flow type

Select the type of hardware flow control from this list.

RTS/CTS: This is the normal form of hardware handshaking. The computer signals with the RTS (Request To Send) signal, that it would like to send data to the CNC, while the CNC sets CTS (Clear To Send) when it is ready to receive data.
DTR/DSR: The DTR (Data Terminal Ready) and DSR (Data Set Ready) signals can be used for handshaking purposes, too. The DNC signals with DTR that it is ready to send and receive data, while the CNC sets DSR.

XOn/XOff characters

The default character for XOn is ASCII 17, also known as DC1 (Device Control 1), and ASCII 19 (DC3) for XOff.

Some CNC use non-standard XOn/XOff characters, if this is the case, you can select the correct XOn/XOff characters from these lists. If you are not sure set XOn to DC1, and XOff to DC3 (the default values).

Set RTS high

If the RTS signal is not used for hardware handshaking you can set it to either high or low by checking this box.

If you are not sure, check this field.

Set DTR high

If the DTR signal is not used for hardware handshaking you can set it to either high or low by checking this box.

If you are not sure, check this field.

Error checking

Ignore errors

Check this field if you want to ignore transmission errors. If errors are ignored, no failed reception reports are generated.

You should never use this option unless there is a problem with your CNC. If you experience a large number of transmission errors, it is usually caused by one of two things: Bad cabling or incorrect port settings.

Please refer to the Troubleshooting section for further information.

Insert parity error character

Check this field if you want to insert a special character in the data stream when a parity error is detected.

No character will be inserted on other types of error (frame, break, ...)

Insert on parity error

If parity is selected (Even/Odd/Mark/Space), and Insert error character is enabled, a special character will be inserted in the data stream when a parity error is detected. You can select the error character from this list.

You should choose a character that is easy to identify when viewing the NC program in a text editor. The default character is #.