VIX AE SERVO DRIVE USER GUIDE

58

Reporting the Status of Variables

By examining Table 4-5 you can see that most system variables take a numerical value or
record a simple ON/OFF state (0 or 1 Flags). Certain variables perform a reporting function
that provides you with information on the status of the controller and any drive faults present
in the hardware or user program code.
Status Variable Reporting
Variable ST is a 32-bit double word that contains status information.
When read, ST reports a 32-bit double word pattern of the form:
*0000_0000_0000_---32 bit wide double word---_00001458 32Bit No.
Where a bit is set (displayed as a 1) its bit number can be determined and compared with
the bit number value given in Table 4-4 to determine the Status Information being reported.
Use the Read command to display the ST word pattern, that is ‘aR(ST)’.
Bit Number Status Information
9 Motor energised
10 Motor undefined, use MOTOR command
16 Duty cycle too high, excessive motor current (I2t)
23 Tracking limit is greater than max. allowed position error
24 Last SETUPFB command failed
25 In motion, 0 for positive motion, 1 for negative motion
26 Brake applied, goes to a 1 if the brake is engaged
Table 4-4. Status Bits Description
Status Variable Byte Reporting
A convenient and more compact way of interrogating the status variable is to test it a byte at
a time using the STn within a read command, where n is used to select the byte to be tested.
For example to read or test the first 8 bits (first byte) of the ST variable status word, use ST1.
Since the status word consists of 4 bytes the relevant part of the word can be read using
ST1 (bits 1 to 8), ST2 (bits 9 to 16), ST3 (bits 17 to 24) or ST4 (bits 25 to 32).
Status Bit 23
The maximum allowed position error will depend on the gains used. Normally there is no
restriction, but for high gains the value of tracking limit (TL) will be restricted to a fixed value
(capped). Status bit 23 is set if the tracking limit is capped.