SRS Labs CTC100, Руководство пользователя

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Remote Programming 114
CTC100 Programmable Temperature Controller
' start with the feedback turned off
Out1.PID.mode = off
' this loop repeats indefinitely
while (1) {
' wait for DIO bit 0 to go high, then turn feedback on
while (DIO & 0x01 = 0) { pause 0.25 s }
Out1.PID.mode = manual
' wait for DIO bit 0 to go low, then turn feedback off
while (DIO & 0x01 = 1) { pause 0.25 s }
Out1.PID.mode = off
}
The next macro lets DIO bit 1 control which temperature sensor serves as the input for channel
feedback loop:
[
#x = DIO
#x &= 2
' if bit 1 is clear and the PID input channel is not In 1,
' set the PID input channel to In 1
if (#x==0 && Out1.PID.input!=$In 1) { Out1.PID.input=(In 1) }
' if bit 1 is set and the PID input channel is not In 2,
' set the PID input channel to In 2
if (#x==2 && Out1.PID.input!=$In 2) { Out1.PID.input=(In 2) }
pause 0.25 s
]-1
Within an if or while
as a query. If the $ prefix were left out, the statement would attempt to compare the name of the
PID input channel to the value of channel In 1
In 1
Drive a so lid state relay w ith the digital IO lines
In some high-power applications, the current to a heating or cooling unit is provided by an
external power supply and modulated with an external solid state relay (SSR). To modulate the
heater or cooler power and obtain accurate temperature control, a variable duty cycle square
wave, similar to pulse width modulation but typically with a cycle time of several seconds, is
required from the CTC100. For example, to supply half of the maximum power to the heater, the
CTC100 would need to turn the relay on for 5 seconds, off for 5 seconds, on for 5 seconds, etc.
The following procedure transforms the output of a PID feedback loop into a variable duty cycle
relay. The macro works well as long as a period of about 10 seconds or longer and a resolution of
0.1 seconds is acceptable. If a much shorter period or greater resolution is needed, it would be
better to fabricate an external analog-to-PWM circuit and drive it with an analog I/O channel.
First, make channel V1 the feedback output, and make it produce a value between 0 and 100.
To do this, select channel V1 and set the following parameters:
"off" for now