
Analog Velocity Control
10
Simple Possibilities to Set Command Velocity with a Potentiometer
M
GND
V7
+ 24V DC
V6
U
B
2,7k
LED
V4
V2
V1
RXD
TXD
+
_
Analog
Input
AGND
V5
V3
n
com
10k
10k
M
GND
V7
+ 24V DC
V6
U
B
2,7k
LED
V4
V2
V1
RXD
TXD
+
_
Analog
Input
AGND
V5
V3
n
com
1k
10k
20V
4,7k
4,7k
Diagram 2 shows the simplest possibility, but
note the following:
■
The command velocity depends on the supply
voltage.
■
The command velocity is not very accurate
due to the changes in voltage at the TXD
connector.
■
The RS-232 port cannot be used.
Diagram 3 shows a more precise circuit, but
note the following:
■
The analog GND is separate from the supply
GND.
■
The RS-232 is available.
Some Comments about the Input Circuit
The input circuit at the analog input is layed out
as a differential amplifier. If the analog input is
“open” there is already a voltage of 2 V. That
means in this case that the motor would be
turning at a speed of about 2000 rpm. In order
to set 0 rpm the input must be connected over a
low ohm resistor to the analog ground (AGND)
or connected to the AGND-voltage level.
Diagram 2
Diagram 3
Содержание MCDC2805 series
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