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ACM1015 Advanced Technical Manual
MODE 3: ANALOG SPEED CONTROL, OPEN LOOP
In Mode 3, the motor speed is set using a voltage from 0 to 5V into Analog input ANA1. This is measured and scaled to a
value from 0 to 100%. ACM1015 uses the speed set-point to generate a 0 to 100% PWM control signal to the motor.
The relationship between the percentage setpoint value and actual motor speed is dependent on the motor and the
motor’s operating profile. It is approximately linear in most applications.
ACM1015 will measure the actual speed of the motor using the tach signal but will not make any adjustments based on
the actual motor RPM.
The Minimum Speed Adjustment Register (Register 8) limits the lowest speed that can be set using ANA1. This is also
expressed as a percentage value.
Registers relevant to this mode:
• Register 7 “Analog 1 Input” (R)
– Analog Input ANA1 level, values from 0 to 1000
• Register 8 “Minimum Speed Limit Setting” (R/W)
– Minimum speed applied to the motor: 0 to 100%
• Register 12 “Current Motor Speed Instruction” (R)
– Power signal applied to the motor by the ACM1015. Identical to Register 1
(R/W) = Read/Write
(R) = Read Only
MODE 4: ANALOG SPEED CONTROL, CLOSED-LOOP USING ANALOG FEEDBACK
Mode 1 is typically used to hold an analog controlled pressure or temperature set-point. The analog sensor should provide
a 0 to 5Vdc signal to the ANA2 control terminal.
The reference set-point is controlled by the analog level on ANA1. Once Mode 4 is enabled, ACM1015 measures the
voltages on both analog control inputs and scales them to a 0.100% value. The error is fed into the internal PID controller.
The PID controller then calculates and sets the actual motor speed using the P, I and D coefficients.
Registers relevant to this mode:
• Register 3 – ‘P’ coefficient. Sets closed-loop gain (Write)
• Register 4 – ‘I’ coefficient. Sets closed-loop integrator (Write)
• Register 5 – ‘D’ coefficient. Sets closed-loop differentiator (Write)
• Register7 – Analog Input ANA1 level from 0 to 1000 (Read)
• Register 12 – Actual motor speed value / output of PID controller (Read)
• Register 20 – Sets the time between PID updates in 0.1 second increments (Write)
• Register 24 – Analog Input ANA2 level from 0..1000 (Read)
