THOMSON Electrak MD Series Installation Manual page 21

5.2.3 Sleep operation
The Electrak MD utilizes a sleep mode operation when positioning is no longer required. This feature
allows for a constant battery connection with minimal drain while the engine or vehicle is not running.
After 5 seconds of bus inactivity, the actuator will put itself in a state of sleep. During this state the
quiescent current is <1 mA for 12 Vdc models and <2 mA for 24 Vdc models. When bus activity is
restored the actuator will begin a wake up phase, followed by an address claim request.
5.2.4 J1939 actuator control message (ACM)
All actuator control parameters are adjustable through the proprietary A message (PGN 61184). The
preferred transmission repetition rate is 100ms (can also be sent as required by the application.)
Additional message specific information can be found in the table below, all other Proprietary A
information can be found in the SAE J1939/21 specification.
Actuator Control Message Signal Information
Start position Length
1.1 14 bits
2.7 9 bits
3.8 5 bits
4.5 1 bit
4.6 35 bits
The least significant bit of each message is indicated by the start position column
5.2.4.1 Position command
This 14-bit signal is used to set the target position for the next actuator motion. Although resolution
of the signal is represented as 0.1 mm/bit, true positional accuracy will be dependent on the stroke
length of the given model. The actuator uses an internally calculated deadband value to determine
when within a target position range. The 0.0 mm and full extend stroke values represent 0 to 100%
stroke and are only relative to the actual available stroke of the individual unit.
Range: 0.0 mm to 300.0 mm
Resolution: 0.1 mm/bit, 0 offset
5.2.4.2 Current limit
This 9-bit signal is used to set a current at which the actuator will cease motion. In the event a
force is applied to the actuator that causes the motor current to exceed this settable value for more
than 50 ms, the actuator will stop any current motion and activate a dynamic braking effect on the
motor. This current limit does not apply during the motor starting phase where in rush current can be
significantly higher than normal running. The max. current for each individual actuator can be found
on the product label.
Range: 0.0 A to 8.0 A (12 Vdc actuator), 0.0 A to 4.0 A (24 Vdc actuator)
Resolution: 0.1 A/bit, 0 offset
5.2.4.3 Speed command
This 5-bit signal is used to set the speed of the actuator. The signal adjusts the PWM driver within
the actuator and the voltage applied to the motor. The resultant actuator speed will be a ratio of the
actuators max speed and also dependent on the load applied to the actuator.
Range: 20% to 100% motor duty cycle
Note: The PWM driver will not provide enough voltage for the motor to operate properly below 20% utilization, therefore, 20%
shoud be considered a lower limit for speed control.
Resolution: 5%/bit, 0 offset
5.2.4.4 Motion enable
This 1-bit signal is used to enable motion from the actuator. If this bit is low (0), no motion will be
allowed. This signal can be used to define the next actuator movement message without starting the
motor. When movement is required this bit can be changed to high (1) and motion will begin using
the other parameter signals encoded in the ACM.
Thomson Electrak MD Actuator - Installation Manual - 2020-02
®
Parameter name
Position command
Current limit
Speed command
Motion enable
Factory use
Thomson
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