Servo RS232 Communication

I'm looking for some information on how to use RS232 communication. I'm designing an automated hoist system using sevo motors and will be using a SLC 5/03 and a Panelview 1000. The design currently uses AB encoders and a HSCE2 counter module and dc motors. I want to replace the DC motors with servo motors. The servo motors can communicate with either 7 discrete inputs or outputs or communicate by RS232. My question is, how to do this using RS232? Where is the information from the servo sent to in the plc. How do I give the servo instructions from the plc. Any direction you can give me would be a big help.

I may be off base here but most servo motors are designed more for high speed/positioning apps than lifting apps like a hoist. Servos arent large motors and usually do not have a lot of torque. They also need a drive/amplifier to use for control which is usually the same device that connects to a plc/pc thru RS232.

You may want to mention what brand/model servo motors you plan to use.

Out of curiousity since this is a hoist/lift application why arent you going with the standard AC Motor/Inverter?

Consider a field bus.

Consider Profibus DP, DeviceNet or Modbus Plus or trading the 5/03 for a 5/05 and use Ethernet.

How do you plan to talk to two or RS-232 devices at the same time? You did say servoS.

The communication speed will be much higher and more reliable with a fieldbus too.

Well, you must have some Servo Drives to run these motors and that's what your SLC 500 will be talking to. You'll need to verify that your drive (indexer), will accept one of the AB protocols.
Then you can use the Message Commands to read and write to the Servo Drive.

Your PLC will essentially manipulate and start motion profiles that reside within the Servo Drive.

This answer is based on "observations" not actual experinence so take it with a grain of salt.

Orn

If you look in your RSlogix help file, you will find several ascii related commands. AWA- ASCII write append and ARD- ASCII read characters are the principal instructions. The help file gives a decent description these and the other related instructions.

The serial link is comm port 1 on the 5/03. The comms are handled outside of the logic scan. There is an input buffer and output buffer. The SLC program reads/writes from there. You have to find out from the servo manual the format of the ASCII strings that you need to communicate. In the past I have used the ST (string) data type. You can embed N and F numbers in a string. Sending is a lot easier than recieving as far as data is concerned. You will have to figure out get it out of whatever string of characters the servo sends you. If you need to send a lot of data, the preferred method is via some sort of I/O bus as mentioned before. They handle all the error checking and stuff, too.

You probably will use a combination of discrete logic lines and serial comms. You use the logic lines for stuff like start, stop, which position to go to, etc. You use the serial link for numerical data and such. Like where is position 1? What is the lift speed? What is the accel rate? If that stuff doesn't need to be changed on the fly, it is much easier to use the discrete lines.

you have the same problem i do

you need the software that supports that drive so you can chek paramerters and drive settings like speed axis directions and so on
im trying to find a free copy of the software and download it because rockwell wants us to buy another ultradrive to get the soft ware a guy quit and stole it or you can say he just took it if you have that you should not have any problem.and if you do can iget a copy please