I have set Slot 1 to Master on the Device Configuration dialog box in akYtec ALP but it doesn’t work properly. What should I check?

First of all, this problem can be caused by a wrong position of jumpers. There are two jumpers, XP4 and XP5, on the RS485 interface card of the PR200. They can be set either to Master or to Slave:

By default upon delivery, they are set to Slave. To use the interface as Master, the jumpers must be set to the M position:

If the jumpers are set to Master and the communication problems still occur, you should check if:

- all the devices on the network have the same network parameters (protocol, baud rate, parity, stop bits and data bits)

- there is only one Master (in this case the PR200) on the network

- all wires are connected properly and there are no loose wires

- signal cables are screened or routed separately from power cables

- the secondary devices on the network are connected to the PR200 in a linear (bus) topology, meaning each device is directly connected to a common line (the bus), and all signals are transmitted from one end to the other

- there are terminating resistors at both ends of the communication bus. Experience shows that the most efficient practice is to use terminating resistors of 150 ohm.