1) Get a pci or isa bus card for your pc that has an RS485 serial port. As much as just buying a GE Fanuc or Horner Electric cable/converter. Pin-out at '[email protected]', mailto:[email protected]. FANUC: RS232 Communication Setting up your FANUC control for RS232 Communications. Straight through cable to reach your Fadal (or Fanuc Control) and you are now properly connected at whatever length you need. We offer straight through cables in 10', 25', 50' & 100' lengths.
Anyone know where to locate the pdf for this control? I believe it is number B-61803E. Or if anyone can clear up a communications cable issue I am having. I checked out the RS232 diagram on and had a couple questions. Here is the layout: -DB-25 pin#/DB-9 pin# -Shield 1 -Transmit Data (TD) from DTE to DCE 2 3 -Receive Data (RD) from DCE to DTE 3 2 -Request to Send 4 7 -Clear to Send (CTS) 5 8 -DCE Ready (DSR) 6 6 -Signal Ground (SG) 7 5 -Received Line Signal Detector (DCD) 8 1 -DTE Ready (DTR) 20 4 -Ring Indicator 22 9 Now what does pin 1 (Shield) on the DB-25 connect to? Earth Ground somewhere? Also, must pins 6,8, and 20 be jumpered together right away, or only if I get alarm 86?
Thanks for any clarifications. Daze: My guess is 2 to 2, 3 to 3, and 7 to 5. Pin 1 at CNC to shield.
No connection of shield at the PC. Cable has 25 pin male connector at CNC, and 9 pin female at PC. Jumper 6, 8, and 20, and separately 4 and 5 at the CNC. Probably do not need jumpers at the PC. With this cable you must operate in a software handshake mode, XON/XOFF.
At the PC under Windows disable the FIFO buffers for your COM channel via Device Manager. Consider our I232 Isolator System to reduce electrical noise problems, provide long cable length capability at high baud rates, and avoid damage from large voltage differences. , 11:16 AM: Message edited by: gar.
ProductionPal: Yes a changing magnetic field will induce a voltage (current) in a loop of wire. It is true that if a shielded cable has the shield connected to an internal wire at one end that is being shielded there will be a loop created. However, this is sort of like a coaxial cable. There are many parallel incremental loops. About 1/2 of the loops are out of phase with the other half. If the changing magnetic field is the same intensity on either side of the center conductor, then the induced voltages are about equal in magnitude and thus we get cancelation.
If symmetry is lacking, then there will be less than perfect cancelation. If the shield is disconnected at the far end, then someting else has to serve as the return path for the signal. This is usually another wire, common (ground), in the cable. So we are back to a loop again even if the shield is only connected at one end. At low frequencies, approximately below VHF, a conductive shield (non-magnetic material) produces negligible shielding of magnetic fields. Thus, the shield is of no value for minimizing noise from changing magnetic fields.
So in some sense the coaxial cable effect may be of value. But I am not recommending connecting the electrostatic shield at both ends. I do not thing it is a big issue. What is important to minimize the magnetic field problems is to use a twisted pair for common and signal.
This will be very effective for varying magnetic fields even without an electrostatic shield. The electrostatic shield is used primarily for minimizing noise from capacitively coupled noise (electric fields). A very big problem is ground path noise. In an unbalanced system, a normal RS232 connection, this results in a voltage difference between sender and receiver from current flow in the ground resistance between the two ends, and that adds or subtracts from the signal being sent. If big enough, maybe 3 V, then data errors are produced. ProductionPal: I do not have a recommendation as to whether or not to ground the shield at both ends.
And it is expected that many should be confused. Using the philosophy of only grounding the shield at one end is good. But in many cases it may not be a problem to tie the shield to machine chassis at bot ends. If we eliminate connecting the shields thru the RS232 connectors, then I would definitely not connect both ends to something that looks like a ground. For example copper water pipes. Maybe the water pipes at both ends are not really connected together and have substantial potential difference between them.
Or rods in the ground. The reason is that there might be a lot of energy available and it might burn up the shield. In some applications this might burn up other conductors and components. As a specific illustration.
On a machine at Chrysler Eldon Ave. On which I had an LVDT on a shim verifier on a structure made of some heavy square steel tubing, probably 4' sq and 1/4' wall, and bolted to the main machine frame, some welder burned up my shield by putting their ground wire on the main machine frame instead of on the part of the structure adjacent to where they were welding.
So there had to be a somewhat poor joint at the bolted on point and their welding current was trying to go thru my shield. Back to the RS232 cable question. On a HAAS machine I would not connect the shield at both ends.
On all used pins except pin 1 (the shield and machine chassis point) they have a 100 ohm 1/4 W resistor in series with the incoming line. Whereas pin 1 is connected directly to machine chassis. The 100 ohm resistor is followed by an 18 V Transorb bi-directional Zener. Externally I have experimented with a similar circuit and with 120 VAC applied to the resistor I burn out the resistor without damage to the Transorb. This type of protection is not usually found at the computer end and I do not know how many other CNC manufacturers might use this protection. In this case by not grounding the shield at both ends we do not have a cable problem from a large difference in ground potentials at both ends causing the cable shield to burn up. On my web site there is a discussion on one way you can get a large voltage difference between computer ground and CNC ground even with both ends connected to the electrical safety ground.
The best way to solve these noise problems is with electrical isolation between the PC and CNC, such as with our I232 Isolator System. See NOISE and GROUNDING at. I believe that many of the PC to CNC RS232 noise problems are the result of ground path noise sources.