C Control The I Unit-M Advanced 5 Vdc Inputs / outputs 16 x digital I/Os / 8 x analogue or digital I/Os Program memory 2 198805 Datenbogen

The C-Control Computer offers  eight A/D ports and two D/A-ports (witch servo drive capabilities as alternate 
function). The maximum input conversion range of the A/D-converters is fixed by the applied reference 
voltage. The maximum output voltage of the D/A-converters is independent of the reference voltage and 
always as high (and accurate) as the operating voltage.  
Reference voltage 
Before using the A/D-converters, the reference voltage has to be connected with the reverence voltage input 
of the C-Control Computer. This voltage defines the maximum input voltage applied to the A/D converters 
and will cause a A/D conversion result of 255. For the most applications the 5V operating voltage is sufficient 
accurate and can directly be used as reference voltage. (Jumper REF onboard the Unit) If more precission is 
required, an external reference voltage can be applied to the Uref input. All measurements of the A/D 
converters are related to GND  
 

All kind of sensors may be connected to the A/D-ports, if they match the maximum A/D input voltage. The 
A/D converters have 8 bit resolution i.e one digit corresponds to 19.6mV. Protect the A/D-ports with a 10k 
serial resistor if the input voltage applied to the ports can exeed voltages above 5V. This resistor will not 
affect the conversion accuracy and provides a over voltage protection up to 12V.See chapter CONFIG 
REGISTER for informations on use the AD ports in digital mode and chapter INSTRUCTIONS AND 
KEYWORDS for informations on reading an analog port 

 

 
 

The two 8 bit D/A converter are PWM (Pulse Width Modulated) converters. The output pulse consissts of 
256 seperate sections swiched to logic lo or hi related to value of the D/A conversion output. If a conversion 
output of 128 is required, 128 sections are set to hi and the remaining 127 sections are hold lo. This 
waveform is repeated at a rate of 1930Hz, each single section is of 2us width. To convert this PWM signal 
into a true analog value a simple RC low pass filter is working fine. Attention has to be paid to the remaining 
ripple (deviations from ac onstant output voltage, varying with tim) which depend on the load, connected to 
the RC filter. For more precision an active circuit is recommended. Driving lamps or LEDs with this PWM do 
not require a filter because the repetition rate is to fast to be realised as flickering of light. Please note that a 
filtered PWM output is not exactly at zero volts if the D/A converter output is set to zero. The reason is that 
the port output lo voltage is approx. 50mV and a 2us pulse is remaining at the D/A output even the converter 
is programmed to a zero output. In this case the filter output will be around 70mV for a D/A converter output 
programmed to zero. The D/A-ports can be programmed for an alternate servo drive 
 
function. See chapter CONFIG REGISTER for informations on use in Servo Mode and chapter 
INSTRUCTIONS AND KEYWORDS for informations on writing to an analog port 

 

 
 
 

 

System Properties are predefined Symbols and can be usually be read or write 

The "Beep" Instruction generates a square wave output at the Beep port. The BEEP port is always an output 
and usually connected to a piezo buzzer. He serves for program or alert status indications during normal 
program operation. During debugging your program this buzzer may be useful also. The audio frequency 
ranges from 10kHz to 100Hz. The Tone parameter may range from 1 to app 100. For larger values the 
change in frequency is almost not audible.