Using USS Protocol Instructions to Communicate with Drives
11-8
S7-200 Programmable Controller System Manual
A5E00066097-02
The RSP_R (Response Received) bit acknowledges a response from the drive. All
the ACTIVE drives are polled for the latest drive status information. Each time the
CPU receives a response from the drive, the RSP_R bit is turned on for one scan
and all the following values are updated.
ERR is an error byte that contains the result of the latest communication request to
the drive. Table 11-6 on page 11-16 defines the possible error conditions that may
result from executing
the instruction.
STATUS is the raw value of the status word returned by the drive. Figure 11-4
shows the status bits for Standard Status Word and Main Feedback.
SPEED is drive speed as a percentage of full speed (-200.0% to 200.0%).
Note
Some drives only report speed as a positive value. If the speed is negative, the
drive reports the speed as positive but reverses the DIR_CW (direction) bit.
RUN_EN (RUN Enable) indicates whether the drive is running (1) or stopped (0).
DIR_CW indicates the drive’s direction of rotation (0 - counterclockwise,
1 - clockwise).
INHIBIT indicates the state of the inhibit bit on the drive (0 - not inhibited,
1 - inhibited). To clear the inhibit bit, the FAULT bit must be off, and the RUN,
OFF2, and OFF3 inputs must also be off.
FAULT indicates the state of the fault bit (0 - no fault, 1 - fault). The drive displays
the fault code. (Refer to the manual for your drive). To clear the FAULT bit, correct
the cause of the fault and turn on the F_ACK bit.
Table 11-3 shows the operands and data types of the DRV_CTRL subroutine.
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