Connecting RS232/Channel 0 port on my V17 or V18 Logix processor to connect to my ProSoft device halts communications..
This is a known issue with Allen Bradley and AB Technote #67950 has been created.
"There is an anomaly with all Logix processors in V17 and V18 in which the serial port UART may stall when transmitting packets. This has only appeared on certain devices connected to the serial port and is dependent upon the electrical load placed on the port. (not all devices can cause this issue to occur)...."
Please see AB Technote #67950 for more information, along with a sample ladder (.ACD file) work-around.