Operating instructions

12 1892 1210 - ST500 Transmitter Operating Instructions - v2.12 / May 2007
CHANNEL SELECTION DURING OPERATION
There are three ways to select a channel during operation:
v In hardware, using three logic lines to select channels 0-7
v Using the SXn00.exe software and a serial connection from a PC to the unit
v By sending a short serial data message to the unit from your own equipment.
Parallel Channel Selection
v The unit must have been left in parallel mode when it was programmed.
v Only channels 0 - 7 are available in this mode
The channel in use depends on the logic levels supplied to PL3 pins 11 to 13, as set out
in the table below. If no connections are made, the unit defaults to channel 0.
CHANNEL SELECTION
PIN 13 (RB3) PIN 12 (RB2) PIN 11 (RB1) CHANNEL
LOW LOW LOW 7
LOW LOW HIGH 6
LOW HIGH LOW 5
LOW HIGH HIGH 4
HIGH LOW LOW 3
HIGH LOW HIGH 2
HIGH HIGH LOW 1
HIGH HIGH HIGH 0
The logic levels are : LOW < 0.8V
HIGH > 2V or floating
Serial Channel Selection (using SXn00.exe)
If the unit was programmed for serial channel selection, it will operate on the channel
nominated at that time. This setting is remembered during unit power off.
The channel can be changed by entering a serial channel number and issuing the
Program Serial Channel command whenever the PC is connected to the unit.
By making up a special adaptor, the PC could be connected to the unit in situ while it is
operating.