danw
Lifetime Supporting Member
Although the ASCII devices are not Modbus ASCII, you should be aware that Modbus ASCII uses a 7 bit word: one start bit, 7 data bits, a parity bit and 1 stop bit.
A couple of vendor app programs that I have use 7 bit ASCII as well, and this aspect becomes an issue when Hyperterminal is used because Hyperterminal does not save the correct comm setup when 7 bit is used. When Hyperterminal is closed and re-opened with a saved setup, it won't communicate with a 7 bit ASCII device because it re-launches configured for 8 bit data words.
All that verbiage because you have a single serial port on the CLX which (presumably) can only accept one set of comm parameters (baud rate, bits/word, parity). Mixing 7 bit and 8 bit words on the same serial line is not doable. The Modbus RTU device will not recognize the 7 bit words and the ASCII enabled devices probably won't recognize the 8 bit words.
But you can prove this true or false by connecting to each device individually with the 'wrong' bits/word setting and see if cmnom works.
A couple of vendor app programs that I have use 7 bit ASCII as well, and this aspect becomes an issue when Hyperterminal is used because Hyperterminal does not save the correct comm setup when 7 bit is used. When Hyperterminal is closed and re-opened with a saved setup, it won't communicate with a 7 bit ASCII device because it re-launches configured for 8 bit data words.
All that verbiage because you have a single serial port on the CLX which (presumably) can only accept one set of comm parameters (baud rate, bits/word, parity). Mixing 7 bit and 8 bit words on the same serial line is not doable. The Modbus RTU device will not recognize the 7 bit words and the ASCII enabled devices probably won't recognize the 8 bit words.
But you can prove this true or false by connecting to each device individually with the 'wrong' bits/word setting and see if cmnom works.