Galil Motion Control RIO-47120, Руководство пользователя

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Input Impedance (With +-10V option)
Single Ended: 42k
Ω
Differential: 31k
Ω
See the AQ command in the command reference for a full explanation.
Analog Process Control Loop
A Process Control Loop allows closed loop control of a process or device. The RIO-471x0 has two
independent PID filters to provide process control of two devices simultaneously. The RIO-471x2 has a total
of 6 PID loops available. The default configuration for the RIO-472xx has no analog outputs and therefore 0
PID loops. If the RIO-472xx is ordered with analog outputs, then it will have 2 PID loops available. The set
of commands shown in the table below are used to set the structure of the Process Control Loop.
Command Description
AF Analog Input for feedback
AZ Analog Output for control
KP Proportional Gain
KD Derivative Gain
KI Integral Gain
IL Integrator Limit
DB Deadband
CL Control Loop Update Rate
PS Commanded Setpoint
TE Tell Error
AQ Analog Input Range
DQ Analog Output Range
*Note – All PID parameters are burnable except PS, DB, AQ, and DQ. If you issue a BN with the PID’s
enabled the default values for PS,DB,AQ, and DQ will be in effect upon power up.
To understand how a Process Control Loop works on the RIO, consider an example where it is desirable to
control the temperature of an oven. The key items needed to do this are a heater, a temperature sensor, the
oven itself, and a RIO unit to control the process. As shown in the diagram below, the heating element is
coupled to the “System” which in this case is the oven. The temperature sensor provides feedback to the RIO
in the form of an analog input. The RIO unit then compares the desired set-point (entered by the PS
command) with the temperature sensor. The difference between the two is called the error “E”. The error
goes through a PID digital filter and then through a Digital to Analog Converter (DAC) which outputs a
control voltage to the heater to close the loop.
PID Digital
Filter
Σ
DAC Heater System
Temperature
Sensor
Kh
Τ
Ks
+
-
V
RIO-47100
Temperature
Setpoint
(PS)
Feedback
(Volts)
E
ADC
Figure 7: Process Control Loop
RIO-47xxx Chapter 4 I/O ● 47