nkhan

Im using a unistream 7 to communicate over serial with a pump. I am able to set settings over using the COM Tx and Message composer, however I am encountering issues with the COM Rx command. I can set rates and volumes without a problem, however I want to also grab the max rate and volume from the pump at the start of the app or when a user pushes a button. I should be able to send "read limit parameter", which then returns the max rate, min rate, max volume, min volume, The following is the return from putty. read limit parameter 29.12145 0.00010 29.31703 0.00269 > However it often takes pushing the button two times to send the command to get a response back. Does the buffer need to be cleared after a read and if so, whats the easiest way to do that? Also, the message that comes back is cut off in the buffer. I only see "read limit parameter" on the receive message. The numbers do not show up in the buffer. I am using the store buffer into tag command to show the information in a string box on the HMI. Ive tried changing the buffer size but it still doesnt help. Any other suggestions on where to investigate the timing issue and the missing data issue? Thanks

Just an update in case others stumble upon this thread. After also trying a serial module (UAC-01RS2) and also having no luck. I started to dig into the hardware manual of the pump I was trying to communicate with. It was saying to include a /r and /n after text commands, however finding a labview program for the pump and going into their functions, it was really Return Carriage and Line Feed that was being sent over with the ASCII text command, not just /r /n. So adding an ETX in the unilogic message composer of ascii characters 13 and 10 for RC and LF, I was finally able to get my project done. After that ETX it was smooth sailing. I was able to communicate with both the USB panel and the serial module without issues.

Maybe I was not clear. The microusb is being used for programming and is connected to my PC. The pump is connected to the Type A Host ports. I tried disconnecting the PC before testing but still no luck. I thought maybe there could be interference between programming port and host port utilization.

Im having issues with getting communication from a Unistream 7 to a syringe pump through a usb to RS232 cable. I am trying to use the message composer to send commands over but have not been successful. The brand of pump I am using is Chemyx (https://www.chemyx.com/support/knowledge-base/programming-and-computer-control/serial-rs232-commands/) The cable is good as I can take that same cable, connect to a PC, connect thru putty thru its COM port, and type commands without an issue. I enabled "USB for Serial Communication" under the PLC communication tab only changing the Baud rate to 38400 and message composer was setup with text strings following Unistreams guide but I was not successful in getting communication (http://support.unitronics.com/index.php?/selfhelp/view-article/unistream-and-communication-with-3rd-party-devices). Any ideas as to why I cant send a "start" string or "stop" string? Also does it matter if I use USB 1 or 2? Would a UAC-01RS2 serial module help? I am using the microusb port to connect to the PLC if that matters Thanks