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Half duplex RS485 coms.
shr00m-dew
Posts: 394
So I'll admit this is the first time I've had to deal with rs485. Talking to a Compool 3830 unit that is in no way compatible with the AMX module. I've worked through getting the feedback from the device and most of the commands to the device.
My issue right now is handling the queuing of things. Everything dealing with the compool sits on the RS485 bus and doesn't need to collide with other commands. We've got the controller, CP keypad, spa keypad, and AMX all together.
Reading through the module doc and other files, it says to return to listen/slave mode after sending a command and to check the line to make sure it is clear before sending a command. I'm assuming that basically means check to make sure no strings are coming in, send the command, and then check the buffer again before sending another command. Am I correct on that thinking?
Second issue is the associated docs (but not the module doc) says that all devices on the bus needs to be terminated with a 1000ohm resistor. I'm assuming that should go between the TX/RX+ and TX/TX- legs. Also it says the 1000ohm is non-standard and any termination at the interface should be disabled. If there any termination on the AMX com ports for RS485 and if so is there a way to disable it?
Hate to sound like a newb, but the compool is definitely the wrong product to be introduced to RS485 on and I want to make sure I'm getting it right aside from the code.
Thanks,
Kevin D.
My issue right now is handling the queuing of things. Everything dealing with the compool sits on the RS485 bus and doesn't need to collide with other commands. We've got the controller, CP keypad, spa keypad, and AMX all together.
Reading through the module doc and other files, it says to return to listen/slave mode after sending a command and to check the line to make sure it is clear before sending a command. I'm assuming that basically means check to make sure no strings are coming in, send the command, and then check the buffer again before sending another command. Am I correct on that thinking?
Second issue is the associated docs (but not the module doc) says that all devices on the bus needs to be terminated with a 1000ohm resistor. I'm assuming that should go between the TX/RX+ and TX/TX- legs. Also it says the 1000ohm is non-standard and any termination at the interface should be disabled. If there any termination on the AMX com ports for RS485 and if so is there a way to disable it?
Hate to sound like a newb, but the compool is definitely the wrong product to be introduced to RS485 on and I want to make sure I'm getting it right aside from the code.
Thanks,
Kevin D.
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