Pin out rs232 Fagor8050/55

[CNCTech25]

Transmission speed
The CNC can operate at up to 115,200 Baud.

This information is half right. The newer 8055 controls can work at that high of a speed, but the original 8055 controls can only handle up to 9600 baud, which is P0=7 on the serial parameters

[angelw]

This is the information in the Fagor Manual

"Connector X3 - RS232
It is a 9-pin SUB-D type male connector to connect the RS 232 C serial port. The cable shield must be connected to the metallic hood at each end.

Cable length
EIA RS232C standards specify that the capacitance of the cable must not exceed 2500pF; therefore, since average cables have a capacitance between 130pF and 170pF per meter, the maximum length of the cable should not be greater than 1 5m (49ft).

"

Grounding the Shield at both ends (both devices) can lead to Ground Loops. A Ground Loop can occur when any two devices are grounded in Different Places, or if one device is not grounded well enough. For example, you may experience a ground loop when you connect a PC and a CNC control together with a serial data cable, if the CNC machine has a ground stake driven through the shop floor, and your Personal Computer is grounded to the ac wall socket, or if one device is not grounded well enough. The ground loop occurs when there is a different electrical potential between the Grounds of the two devices. This results in an electrical current being conducted through the data cable. and can burn out the IC chips that send and receive the RS232 serial signals, if the difference in potential is greater than about 30 volts. Accordingly, unless good grounding to the same ground can be assured for both devices, its recommended to ground the shield at the CNC end only.

Cable length is highly dependent on the Baud Rate being used, with the Standard being based on a capacitance of 50 pF/foot to allow maximum communication speed of 19200 to occur. If speed is reduced by a factor 2 or 4, the maximum length increases dramatically, as shown in figures obtained by test done by Texas Instruments years ago.

Using a cable with low capacitance allows you to span longer distances without going beyond the limitations of the standard. For example, a cable with a capacitance of 17 pF/ft will allow a maximum cable length of 147 feet (2500pF/17) at maximum speed.

Baud Rate ---- Cable Length
19200 ---------- 50
9600 ------------ 500
4800 ------------ 1000
2400 ------------ 3000

Regards,

Bill