Clay B.
Lifetime Supporting Member
Background:
Using a S7-200 to talk to a Mettler Toledo Weight Controller. The comms is RS-232 serial. I have done this with an AB Micro Logic PLC but now I need to do it with an S7-200.
Problem:
I do not understand how freeport mode works. I have an example from Seimens (Tip 005) but I am just not getting it.
What I need to do is send an ASCII 'P' to the weight controller so it will send back the tare, net and gross weights. Once I have this I will repeat the send. I am attaching the tip program in hopes somone can explain it to me. The problem I have is getting data back. I do not think I understand how the interupts are supposed to work. Also the trigger for the XMT somehow ties into the read interrupt but it only works when I stop the PLC set it to 1 and then restart the plc. Like I said I am confused
Any help would be appriciated.
Also right now I have the PLC writing to a Hyperterminal on a PC so I can see exactly what is being sent and what I am sending.
Using a S7-200 to talk to a Mettler Toledo Weight Controller. The comms is RS-232 serial. I have done this with an AB Micro Logic PLC but now I need to do it with an S7-200.
Problem:
I do not understand how freeport mode works. I have an example from Seimens (Tip 005) but I am just not getting it.
What I need to do is send an ASCII 'P' to the weight controller so it will send back the tare, net and gross weights. Once I have this I will repeat the send. I am attaching the tip program in hopes somone can explain it to me. The problem I have is getting data back. I do not think I understand how the interupts are supposed to work. Also the trigger for the XMT somehow ties into the read interrupt but it only works when I stop the PLC set it to 1 and then restart the plc. Like I said I am confused
Any help would be appriciated.
Also right now I have the PLC writing to a Hyperterminal on a PC so I can see exactly what is being sent and what I am sending.