Burkert Type 8620 - Manual (Page 77)

mxCONTROL Type 8620
Page 77
13.3 Transistor Outputs (Option)
Technical details of the transistor outputs are described in chapter 6.1 “Technical Specifications”.
Transistor outputs can be used for controlling e.g.
• On/Off valves and pumps
• Dosing pumps (Pulse Frequency modulated (PFM-) outputs)
• Proportional valves (PWM / fast PWM output)
Each transistor output can be configured to work as
• Simple On/Off output
• Pulse Frequency modulated (PFM-) output
• Pulse Width modulated (PWM) output
• Fast PWM (pulse width modulated) output.
PFM:
Pulse Frequency Modulation - modulation of a square wave signal with constant pulse duration
(Tpuls). The parameter “Tpuls” can be changed.
PWM:
Pulse Width Modulation - modulation of a square wave signal with constant frequency (Tperiod).
The parameter “Tperiod” can be changed.
The principle of PFM and PWM is shown in Figure 21 and Figure 22.
The configuration of all supported transistor outputs is summarized in chapter 13.3.5.
13.3.1 Transistor output as On/Off-Output
The relation between controller output and transistor output as On/Off-output is similar to the relay
output as On/Off-output. Compare chapter 13.1.1.
13.3.2 Transistor output as PFM Output
The relation between controller output and transistor output as PFM output is similar to the relay
output as PFM output. Compare chapter 13.1.2.
13.3.3 Transistor output as PWM Output
The relation between controller output and transistor output as PWM output is similar to the relay
output as PWM output. Compare chapter 13.1.3.
The period duration is configurable between 0.1 … 9999 seconds.
Limitation of the manipulating speed
In addition, the manipulating speed of the transistor output can be limited. For this purpose, the control
output originating from any module is compared with the currently provided control output in regard to
its change. If the change is greater than the parameterized maximum permitted value, the provided