Thomson
Thomson Electrak
®
MD Actuator - Installation Manual - 2020-02
22
5.2.4.5 Factory use
The remaining 35 bits of the ACM are used for factory calibration use only and should be filled with
0x00 or 0xFF when sending this message.
5.2.5 J1939 actuator feedback message (AFM)
All actuator feedback data can be retrieved through the proprietary A2 message (PGN 126720). This
message is transmitted every 100ms. Additional message specific information can be found in Table
2, all other Proprietary A2 information can be found in the SAE J1939/21 specification.
5.2.5.1 Measured position
This 14-bit signal is used to inform the user of the actual actuator stroke position. 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 it is within a target position range. The 0.0 mm and ordered full extend stroke values
represent 0 to 100% stroke but the signaled value does not take in to account any mechanical
tolerances or play in the actuator.
Range: 0.0 mm to 300.0 mm
Resolution: 0.1 mm/bit, 0 offset
5.2.5.2 Measured current
This 9-bit signal is used to inform the user of the actual current being drawn used by the actuator.
Range: 0.0 A to 20.0 A
Resolution: 0.1 A/bit, 0 offset
5.2.5.3 Running speed
This 5-bit signal is used to inform the user of the actual duty cycle being applied to the motor
through the internal actuator controller.
Range: 0% to 100% motor duty cycle
Resolution: 5%/bit, 0 offset
5.2.5.4 Voltage error
This 2-bit signal is used to inform the user that the operational voltage is outside of allowable
running parameters. Any motion already in progress will continue until completed, but additional
movement request will not be allowed until the operational voltage returns within the normal
Actuator Feedback Message Signal Information
Start position
Length
Parameter name
1.1
14 bits
Measured position
2.7
9 bits
Measured current
3.8
5 bits
Running speed
4.5
2 bits
Voltage error
4.7
2 bits
Temperature error
5.1
1 bit
Motion flag
5.2
1 bit
Overload flag
5.3
1 bit
Backdrive flag
5.4
1 bit
Parameter flag
5.5
1 bit
Saturation flag
5.6
1 bit
Fatal error flag
5.7
26 bits
Factory use
The least significant bit of each message is indicated by the start position column
