Serial Ports on Axcent3 and NI

bano

Can someone please explain the difference between a serial port on an Axcent 3 and an NI controller? I integrated a DSC Maxsys security system into a project, initially assigned to an Axcent3 but it didn’t work. However when I reassigned the Maxsys to a serial port on the NI it worked perfectly. I swapped ports with a receiver and now both devices work, so I know it’s not a bad port. Only differences are baud rates (2400 on Maxsys, 9600 on receiver) and use of RTS connection on pin 7 for Maxsys. AMX Engineering please feel free to chime in.

DHawthorne

Are you setting the baud rate in the ONLINE event? Both controllers will retain whatever the old setting was until you override it.

Failing that, it could just be a bad port. There is no difference I'm aware of between the NI and Axcent3 when it comes to serial ports. If it was the NI that wasn't working, I'd say you had the bad capacitor problem, but it's not like Axcent3 ports never burned out either. Most times I've had them fail there was a static discharge on the connected wire.

bano

DHawthorne wrote: »

Are you setting the baud rate in the ONLINE event? Both controllers will retain whatever the old setting was until you override it.

Failing that, it could just be a bad port. There is no difference I'm aware of between the NI and Axcent3 when it comes to serial ports. If it was the NI that wasn't working, I'd say you had the bad capacitor problem, but it's not like Axcent3 ports never burned out either. Most times I've had them fail there was a static discharge on the connected wire.

It can't be a bad port on the Axcent3 as it is now controlling a receiver. No changes in software beyond port assignments in define device. Baudrate set in Online Event. Same wiring. All I did was to swap ports with the NI and Axcent3.

DHawthorne

There are other setting that may have been applied that the port is remembering from a prior use, that you aren't overriding. Explicitly turn off your hardware and software handshaking (HSOFF and XOFF); CHARD could possibly be a factor too, but it's more likely to cause misfires than no-op problems.

bano

DHawthorne wrote: »

There are other setting that may have been applied that the port is remembering from a prior use, that you aren't overriding. Explicitly turn off your hardware and software handshaking (HSOFF and XOFF); CHARD could possibly be a factor too, but it's more likely to cause misfires than no-op problems.

I'm using a Netlinx module for the maxsys which defines serial port parameters online. I've used this module several times on NI controllers, but never on an Axcent3. It was more of a nuisance than crisis as the controllers were stacked in a rack making it easy to swap ports.

jnizi

This may go back to an old school limitation of data on AXLink. If I remember correctly, the data packet limit was 64 bytes including the header so if you have a longer string being transmitted, things may not work right.