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If the serial RS485 communication does not operate properly, EasyMotion Studio will issue an error message and you’ll see displayed on the status bar (the bottom line) of the EasyMotion Studio the text “Offline”.
| 1. | If the error message is “Cannot open the selected serial port”, the serial port you have selected from “Port” does not exist or is used by another device of your PC (mouse, modem, etc.). Click “Cancel”, reopen Communication | Setup dialogue, the PC serial port used for RS-485 operation and try again. |
| 2. | If the error message is “Cannot synchronize the computer and drive/motor baud rates” click “Cancel”, then check the following: |
| • | RS-485 cable connections, presence of the 120 ohms terminal resistors at the two ends of the network and the presence of the bias circuit(s) to keep the line level in idle mode |
| • | If you use an RS-232/RS-485 converter with automatic control of transmission, check the specifications. Usually these devices free the RS-485 lines when a transmission ends, only after a time equivalent with transmission of another byte. You can’t use these devices, as the Technosoft drives/motors respond to a data request faster. For correct operation you should use a device that frees the RS-485 lines immediately after the last stop bit transmitted |
| • | In EasyMotion Studio project, the “Axis Number” of the selected application. This should match with the Axis ID of one of the drives from the network. As e general rule, the axis number of each application must correspond with the axis ID of one drive from the network. Each drive must have a different axis ID. No drive can have the same axis ID value as that set as Axis ID of PC. |
| • | Drive/motor hardware settings for RS-485 communication (see RS-485 Setup): |
| 3. | If the communication operates usually but gives communication errors from time to time, check the following: |
| • | Network ground connection. This link is mandatory if the drives/motors don’t have the same ground |
| • | In Communication | Setup click on the Advanced …HELP_ADVANCED_COMM_SETUP@Kernel.hlp button and increase the Read interval timeout, Timeout multiplier and Timeout constant parameters. Note that these parameters are related to PC serial operation and usually the default values for these parameters do not need to be modified. |
| • | Try to reduce the baud rate progressively, starting with 115200 |
After you fix the problem, execute menu command “Communication | Refresh” to restore the communication.
See also:
RS-485 Communication Setup
Advanced Communication Setup
Communication Setup
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