Fagor RS232 Communication - No Luck

[cammo]

Hi All,

We have recently purchased (for work) a Fagor NVP200MRS Digital Read Out. This display comes with a rs232 output on it however i am having zero luck in getting it to communicate with the computer.

The plan for this is for the tool positions to be transmitted to a VisualBasic program to store in a database.

I have tried with hyperterm and lookRS232 but netither can talk to, or recieve from, the DRO. The documentation supplied by Fagor is minimal (only parity, baudrate, etc.)

If anyone has any ideas on how to get the PC and DRO talking, I would greatly appreciate it.

Thanks,
Cammo

[gar]

050809-1944 EST USA

Cammo:

For experimenting set baud rate to 9600, stop bits at 1, no parity, and handshake none. Anything you want to set up as a receiver must be set exactly the same way.

For the first test none of these settings matter.

Test 1. Assume the Fagor RS232 connector is a male 25 pin with pin 7 common. Also pin 1 is probably common. Pin 1 is identified as ground, and pin 7 as signal common. These are usually directly shorted together on many systems. When used pin 1 goes to the cable shield, probably only one end. On HAAS machines pin 7 has a 100 ohm resistor from pin 7 to internal common and machine chassis.

Without sending data measure the voltage at pin 2 ( hopefully TxD, serial output from Fagor ) relative to pin 7. This should be about -9 to -12 volts. If it is not, then check pin 3 relative to 7. If this is -9 to -12 volts, then pin 3 is TxD.

Test 2. Put the meter between common and TxD. Now send data and the meter should read an average near zero ( probably within +/- 1 volt ). If this happens you are sending data.

If Fagor has a 9 pin RS232 connector, then pin 5 is common and either 2 or 3 is TxD.


Pins 2 and 3 on either 9 pin or 25 pin connectors are noarmally always the TxD and RxD pins. If you determine which is TxD by the above test, then the other is RxD. When connecting two devices together you must connect TxD at the source to RxD at the destination, and vice versa. This is based on my above definition of TxD being the transmitter at the end of the connection you are testing.

See what this tells us. If your transmission is very short, then it may appear as a blip on the meter. Then set to baud rate of 110 and try again.

.

[cammo]

I may have found the issue. I am using a standard 9 pin serial cable, and as such the handshaking (RTS,CTS, etc) lines are wired straight through. However, the DRO requires the connection to the PC to be a dumb terminal, ie. DTR shorted to DSR, and RTZS shorted CTS, on the PC side. Will wire up a lead (another trip to the electronics shop, bah) and see how it goes.

Cam

[gar]

050809-2041 EST USA

Cammo:

If the hardware handshake lines are properly wired in the cable you should be able to set both ends to hardware handshake ( meaning use RTS to CTS, and RTS to CTS in the opposite direction ) and have successful communication.

If you set both ends to no handshake, you should be able to communicate no matter what is done with the states of CTS unless the circuit and/or software designer did not ignore the CTS input in this no handshake state.

Also the question is whether you can set a no handshake mode at both ends.

(edit ) What is the exact wiring of your cable from end to for all pins? What connectors at each end?
(end edit).

[gar]

050811-1820 EST USA

Cammo:

Have you totally solved your problem?

.

[cammo]

Hi,

Yes, the problem of communicationg with the computer was solved once a new cable was wired up. Now the issue is the fact that the DRO will not allow me to send the displayed data to the computer (just parameters, programs, and tool offsets) and I cannot send a request from the Pc to the DRO. Looks like we'll have to take this one back.

We got this one in the firt place because it, and the Fagor transducer, were a drop in replcaement for the old on. Ahh, the simple solution never is.

Thanks for the help anyways,
Cammo