In-depth study of PROFIdrive drive control protocol (2)
In-depth study of PROFIdrive drive control protocol (2)
In the previous article, we introduced PROFIdrive standard messages 1, 2 and 3. Today in this article we will introduce standard messages 4 and 20, and introduce the control word STW1 and status word ZSW1.
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1. Standard message 4 Standard message 4 is used for speed control and has 2 encoder position feedbacks. It is based on standard message 3, adding the control word (G2_STW), status word (G2_ZSW), and actual position 1 of encoder 2 (G2_XIST1) and actual position 2 (G2_XIST2), its message length is 14 PZD, as shown in the following table:
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2. Standard message 20
Standard message 20 is used for speed control. It uses 16-bit speed setting value (NSOLL_A) and feedback value (NACT_A), and feedbacks the actual motor current (IAIST_GLATT) and actual torque (MIST_GLATT), actual active power (PIST_GLATT) and fault (MELD_NAMUR), as shown in the following table:
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3. Control word 1 (STW1)
Control word 1 (STW1) is used to control the inverter to run, stop, run at a specified speed, and so on.
STW1 includes 16 bits, the definition of each bit is shown in the following table:
Definition of Control Word 1 (STW1)
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The specific description of each bit is as follows:
Bit 0 (OFF1): When the value of this bit changes from 0 to 1, the inverter enters the "ready for operation" state;
When the value of this bit changes to 0, the motor runs according to the ramp time of the ramp-function generator (p1121)
Braking, the inverter turns off the motor after reaching a static state;
Bit 1 (OFF2): When the value of this bit becomes 0, the motor is immediately shut down and coasts to stop; this bit
When the value is 1, it means that the power can be connected;
Bit 2 (OFF3): When the value of this bit becomes 0, the motor follows the OFF3 ramp time (p1135)
Brake until it reaches a static state; when the value of this bit is 1, the inverter turns on the motor power;
Bit 3 (Enable): When the value of this bit is 0, the motor operation is prohibited (pulse blockade); when the value of this bit is 1, the motor operation is enabled;
Bit 4 (EnableRamp): 0=block the ramp function generator, the inverter sets the output of the ramp function generator to 0; 1=do not block the ramp function generator;
Bit 5 (FreezeRamp): 0=Stop the ramp function generator, the inverter keeps the output of the ramp function generator at the current value; 1=Enable the ramp function generator, and the output of the ramp function generator tracks the set value;
Bit 6 (EnableSetPoint): 0=block the setpoint, the motor brakes according to the ramp-function generator time (p1121); 1=enable the setpoint, the motor accelerates to the set speed value according to the ramp-up time (p1120);
Bit 7 (Reset): 0/1 rising edge resets the fault;
8th/9th: reserved;
Bit 10 (ControledByPLC): 0=not controlled by PLC, the inverter ignores the process data from the fieldbus; 1=controlled by the PLC, the inverter will use data from the fieldbus;
The 11th bit (Invert): 1=invert the internal setting value of the inverter;
No. 12: reserved;
13th place: 1=The electric potentiometer is raised, increase the set value saved in the electric potentiometer; 0=no change;
The 14th place: 1 = lower the electric potentiometer, reduce the set value saved in the electric potentiometer; 0 = no change;
No. 15: Reserved. In the standard message 20, it is the CDS bit 0 (CDS=command Data set) to switch between different command data;
4. Status word 1 (ZSW1)
Status word 1 (ZSW1) is used to feedback the status of the inverter, such as whether it is ready, whether it has been running, whether there is a fault/warning, etc. ZSW1 includes 16 bits, the definition of each bit is shown in the following table:
Definition of status word 1 (ZSW1)
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The specific description of each bit is as follows:
Bit 0 (PowerReady): 1=Ready to switch on, the power has been switched on, the electronic components have been initialized, and the pulse is blocked;
The first digit (ReadyForRunning): 1=The motor has been switched on and there is no fault at present (receive the operation enable STW1.3) command, the inverter will switch on the motor;
No. 2 (Running): The motor speed follows the set value;
No. 3 (Fault): 1=fault occurred;
Bit 4 (OFF2_NOT_ACTIVATD): 1=OFF2 is not activated;
Bit 5 (OFF3_NOT_ACTIVATD): 1=OFF3 is not activated
Bit 6 (Inhibit): 1=On prohibition is valid, only when OFF1 command is given and given again
The motor can be switched on after the ON command;
No. 7 (Warning): 1=Warning;
No. 8 (Tolerance): 1=The speed difference is within the tolerance range of 2020/12/28;
Bit 9 (Request): 1=Control has been requested, and the automation system is requested to control the inverter;
The 10th bit (OverMaxSpeed): 1=The speed is greater than or equal to the maximum speed;
Bit 11 (Torque Limit): 1= reach the torque limit (this bit of message 20 1= reach the
Current limit or torque limit);
12th place (Brake): 1=Brake is open;
Bit 13 (OverHeating): 0="Motor overheating" alarm;
No. 14 (Direction): Motor steering,
1=forward rotation (internal actual value of the inverter>0);
0=Reverse (internal actual value of the inverter<0);
Bit 15 (OverLoad): 0="Inverter thermal overload" alarm (message 20: 1=display
CDS);
Well, about PROFIdrive's message 4, message 20, control word 1 (STW1) and status word
(ZSW1) Let's introduce here first, and then we will give an example of PROFIdrive communication between PLC and inverter.