Total_newbie
Member
Hello,
As my user name implies - I am totally new to the wonderful world of PLCs. I have though been tasked with integrating into our larger software package a connection to MicroLogix 1400 controller so that we can simply read/write specific registers. Connection will be via RS232 serial connection. For connection software, I have used https://github.com/robertlarue/DF1Comm/blob/master/DF1Comm/DF1Comm.vb - which is straightforward, with routines which could be easily combined with our software. For serial connection I am going from COM1 port of PC to (9-pin) serial port of MicroLogix controller via null modem cable (wiring as per http://www.home-machine-shop.com/bits/NULL_MODEM_CABLE.jpg). Controller is set to default communication config (19200 baud, no parity - Node is "1").
When I try "autodetect" (which sends DLE -ENQ, varying baud/parity/etc pms to get reply) to make initial connect - I get no response at all. I do not see COMM 1 indicator on controller flash. I know that I am sending out bytes thru port, because if I connect pins 2/3 (send/receive) -I can see echo using terminal emulator on COM1.
Is there something obvious (or not so obvious...) that I may be missing, or something else that I might try? I see that I might try RSLinx software - but I think that if cannot make connection right now - that package will not help me.
One additional point which I just noticed. On my (Windows 10 PC) - if I connect COM1 to COM2 and write thru COM1 - I see echo of out bytes in COM2. On the Windows 7 PC which is connected to controller - with same config, I do not see echo (even though if I cross over pins 2 and 3 - I get echo...). (Is there difference between serial writes?). Unfortunately - I can only connect to controller via Windows 7 machine right now.
Thanks to all for any help or ideas..
As my user name implies - I am totally new to the wonderful world of PLCs. I have though been tasked with integrating into our larger software package a connection to MicroLogix 1400 controller so that we can simply read/write specific registers. Connection will be via RS232 serial connection. For connection software, I have used https://github.com/robertlarue/DF1Comm/blob/master/DF1Comm/DF1Comm.vb - which is straightforward, with routines which could be easily combined with our software. For serial connection I am going from COM1 port of PC to (9-pin) serial port of MicroLogix controller via null modem cable (wiring as per http://www.home-machine-shop.com/bits/NULL_MODEM_CABLE.jpg). Controller is set to default communication config (19200 baud, no parity - Node is "1").
When I try "autodetect" (which sends DLE -ENQ, varying baud/parity/etc pms to get reply) to make initial connect - I get no response at all. I do not see COMM 1 indicator on controller flash. I know that I am sending out bytes thru port, because if I connect pins 2/3 (send/receive) -I can see echo using terminal emulator on COM1.
Is there something obvious (or not so obvious...) that I may be missing, or something else that I might try? I see that I might try RSLinx software - but I think that if cannot make connection right now - that package will not help me.
One additional point which I just noticed. On my (Windows 10 PC) - if I connect COM1 to COM2 and write thru COM1 - I see echo of out bytes in COM2. On the Windows 7 PC which is connected to controller - with same config, I do not see echo (even though if I cross over pins 2 and 3 - I get echo...). (Is there difference between serial writes?). Unfortunately - I can only connect to controller via Windows 7 machine right now.
Thanks to all for any help or ideas..