As a Speed Reference input ( ...01h), Analog input #1 sets the speed of the controlled motor directly if the
If the
The External Torque Limits are used to set limits on the motor current which are below the current limit level. When parameter #5 VL4 VL3 is set to 00 01h, or 00 02h, Analog Input #1 may be set to ...03h or ...04h respectively to supply the torque limiting reference.
The External Horsepower Limit sets the maxi- mum horsepower produced by the drive. Horsepower is the PRODUCT of speed and torque. When motor speed is low, motor current is high, and when speed is high, current is low. The drive increases speed until sufficient load is developed and the product of load and speed equals the setpoint. After that is achieved, increasing load reduces speed, and decreasing load increases speed.
18.ANALOG INPUT #1 SIGNAL CONDITIONING
USE PARAMETER #17 TO SELECT THE FORM OF THE SIGNAL AT ANALOG INPUT #1. RANGE OF VALUES: 0000 0000h to 0000 001Fh
0 TO 32 (decimal)
Default Value: 0000 0001h | 1 (decimal) |
Six types of signals will be accepted by Analog Input #1. Parameter #18 selects the form of signal to be processed.
The six types of signals are:
0000 0000h | |
| bipolar voltage input with zero |
| center value |
0000 0001h | 0 to +10VDC |
| unipolar voltage signal |
0000 0002h | 0 to +5VDC |
| unipolar voltage signal |
0000 0003h | 1 to +5VDC |
| unipolar voltage signal |
0000 0004h | 0 to 20mA |
| unipolar current signal |
0000 0005h | 4 to 20mA |
| unipolar current signal |
0000 0006h | to 0000 001Fh |
| Undefined - Reserved for |
| future use |
If an undefined mode (...06 through ...1F) is selected, Analog Input #1 will be inoperative.
Choosing the incorrect signal conditioning for the actual input signal will result in erratic operation.
19.ANALOG INPUT #1 LOW ENGINEERING UNITS (EGU)
USE PARAMETER #17 TO SELECT THE THRESHOLD OF ANALOG INPUT #1 EFFECT. RANGE OF VALUES: FFFE 7961h to 0001 869Fh
Default Value: 0000 0000h | 0 (decimal) |
(See Parameter 14 for the definition
and purpose of EGU) Parameter #19 sets the threshold level for
effectiveness of Analog Input #1 at the lowest signal level.
Assume that the maximum speed of the 1750 RPM motor is set to 12500 EGU’s in parameter #14 (representing, perhaps, 125.00 RPM on an extruder screw) and the Analog input is set for a Speed Reference Input of 0 to +10VDC. The default value of parameter 19 is 0. This means that when 0VDC is present at Analog Input #1, the result will be zero speed.
Now, if we want to set a minimum speed on this system, we can set a value of 500 in parameter #19. This means that when 0VDC is present at Analog Input #1, the motor will run at a speed of 500/12500 or 4 percent (70 rpm) of the maximum speed of the motor. (see also parameter #20).
Revised 7/95 | Page 25 | |
POWERTEC Ind. Corp.© |
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