Applied Motion ST10-C-CE - Manual (Page 19)

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ST5/10-Si,-Q,-C, IP Hardware manual 920-0004 Rev. F
6/10/14
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 ST 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 ST Configurator 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 ST 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: pin1 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
ST Configurator™ software that came with your drive for this purpose.
Connect the drive to your PC, then launch the ST Configurator™ software. Finally, apply power to your
drive. If you have already configured your drive, then you should click the Upload button so that the ST
Configurator™ settings match those of your drive. Click on the Motion button, then select the “SCL”
operating mode. If you have a Q drive, you may want to select “Q Programming”. Either way, you’ll see the
+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
twisted pair
RS-485 Two Wire System