Upload failures may be experienced if the PLC host Link baud rate is set to 9600 or below and the Response timeout is left at the default 2 seconds. Therefore the PLC and Westermo modem should be set to a baud rate of 19200 or higher or the default Response timeout should be increased to 10 seconds.
The Westermo has a top speed of 57600 and is therefore recommended and used in this example.
Modems without DIP switches must be set up to the following specification using Hyperterminal.
Set the Westermo DIP switches to 57600, 7, E ,2 protocol. Refer to Westermo installation manual for other DIP switch setting details.
Standard settings as below: All off except:
SW2 4 (DTR/DSR disconnected)
SW3 1 (2-wire),4 (Speaker off) and 7 (DCD follows state of line carrier)
SW4 1 & 4 (57600), 5 (7,E) and 8 (2 Stop bits)
SW5 4 (9600 bit/s line modulation)
The modem to PLC connection must contain a cross-over lead as detailed below:
Modem (9 pin male) PLC (9 pin male)
Pin 2 to Pin 3
Pin 3 to Pin 2
Pin 5 to Pin 7
Pin 7 short to Pin 9
Pin 6 short to Pin 7
Pins 1, 4 , 8 & 9 not used. Pins 1, 4, 5, 6 and 8 not used.
Use a serial connection to set the PLC Host Link port to 57600, 7, E, 2 using the "Settings" component of CX-Programmer.
Any standard modem can be used to connect to the PC. The baud rate can be set independent of the "PLC - Westermo" baud rate but should be higher than 4800. A rate of 115200 is recommended. The protocol settings ex. 7, E, 2 must remain the same as set in the PLC.
A protocol of 8, N, 1 can also be used instead of 7, E, 2 but must be used in all settings described in this FAQ. (ie PLC, Westermo and CX-Programmer).
Install the Modem using the standard Windows installation wizard and the appropriate modem driver cd.
Use CX-Programmer to set the "Change PLC", "Network Type" to Sysmac Way. Use the "Settings" and "Modem" tab to select the installed modem. Set the baud rate higher than 4800 eg 115200 and the protocol to 7, E, 2. Select the "Connect To" options ie. Country code, Area code and Telephone Number. These "Connect To" settings are mandatory.
The Modem settings can be set to default in the OS "Control Panel", "Modem" section.
Modem communications can then be successfully established.
The default Response timeout can be increased to 10 seconds in the Network Settings dialog.
