Bimba STP-10 - Manual (Page 14)

STP-10 Hardware Manual
14
Two Wire Systems transmit and receive on the same pair of wires, which can lead to trouble. The host must not only disable its
transmitter before it can receive data, it must do so quickly, before a drive begins to answer a query. The STP-10 drives include a
“transmit delay” parameter that can be adjusted to compensate for a host that is slow to disable its transmitter. This adjustment
can be made over the network using the TD command, or it can be set using the IQ ® Stepper software. It is not necessary to set
the transmit delay in a four wire system.
RS-232 to RS-485 2-wire Converter
Model 485-25E from Integrity Instruments (800-450-2001) works well for converting your PC’s RS-232 port to RS-485. It comes
with everything you need. Connect the adaptor’s “B” pin to the STP-10 drive’s TX+ and RX+ terminals. Connect “A” to the drive’s
TX- and RX- terminals.
Converting USB to RS-485
The USB-COMi-M from www.byterunner.com is an excellent choice for USB to RS-485 conversion. Set SW1 to ON and SW2-4
to OFF. On the USB-COMi-M screw terminal connector: pin 1 goes to RX- and TX-. Connect pin 2 to RX+ and TX+. Pin 6 is
ground. The DB-9 is not used.
Assigning Multi-Drop Addresses
Before wiring all of the drives in a multi-drop network, you’ll need to connect each drive individually to the host computer so that
a unique address can be assigned to each drive. Use the programming cable and the IQ ® Stepper software that came with your
drive for this purpose.
Connect the drive to your PC, then launch the IQ ® Stepper software. Finally, apply power to your drive. If you have already config-
ured your drive, then you should click the Upload button so that the IQ ® Stepper settings match those of your drive. Click on the
Motion button, then select the “SCL” operating mode. If you have an IQ ® drive, you may want to select “IQ ® Programmer”. Either
way, you’ll see the RS-485 Address panel appear. Just click on the address character of your choice. You can use the numer-
als 0..9 or the special characters ! “ # $ % & ‘ ( ) * + , - . / : ; < = > ? @ . Just make sure that each drive on your network has a
unique address. If you are using a 2 wire network, you may need to set the Transmit Delay, too. 10 milliseconds works on the
adapters we’ve tried. Once you’ve made your choices, click Download to save the settings to your drive.
+RX- +TX- GND +RX- +TX- GND +RX- +TX- GND
to PC TX+ (B)
to PC TX- (A)
to PC GND
Drive #1 Drive #2 Drive #3
RS-485 Two Wire System