FEC AFC1500 - Manual (Page 111)

FEC AFC1500 Operations Manual Chapter 6: Fastening Instructions (Rev. 6: 10/09)
Page 6-25
6.6 Added Functions
Additional functions are available in both stand alone SAN Units and Multi Unit configuration. With
the addition of a MUTLI Unit as the main control for a SAN Unit or group of up to 31 SAN Units, addi-
tional fastening functions are available. The MULTI unit assumes control of the SAN Unit I/O and se-
quencing is controlled directly from the MUTLI Unit. An internal user programmed sequence program
controls all fastening function from one set of PLC I/O, instead of connecting every spindle(s) I/O to a
PLC. This drastically reduces the number of I/O and PLC programming, since the sequencing of the
spindles is handled by the MULTI Unit. In addition to this function, the MULTI Unit also adds fasten-
ing data communication options that are not available directly from a SAN Unit. (See the AFC1500
MULTI Unit Hardware Manual for more information)
Some functions in this section are only available with a MULTI Unit configuration. Stand alone
SAN Units DO NOT have all of these functions and have been identified for use with a MULTI
Unit only.
6.6.1 Current Monitoring / Control
The current monitoring function works as a redundant protection for the torque transducer operations.
By sensing the current drawn by the motor, the system can establish an alternate reference to the
signals generated by the torque transducer preamplifier. It is intended to detect problems with the mo-
tor that would not be detected by the torque transducer and also as a maintenance tool to determine
if there is a problem before the system will shut down.
This function allows the operator to set Low Current and High Current Limits. If the current drawn by
the motor overrides the High Current Limit or does not achieve the Low Current Limit, the System ac-
tivates the Current Warning PLC Output Signal, without halting the System's operation. This current
warning signal prompts of a potential failure in the system that requires inspection, but allows the sys-
tem to continue until a suitable time is available.
The Fastening current limit allows a limit for maximum current draw during a fastening cycle. If this is
set below Full Scale Current, then the current will not exceed this value during a fastening cycle. This
function is mainly for protecting a motor during Torque recovery applications. If the Fastening Current
Limit is exceeded and the motor stop turning a Resolver Abnormal fault may occur.
The Full scale current limit is an automatically set reference value. This is generated based upon the
motor/servo(SAN Unit) used and should not be changed.
Fig. 6-6-1 Current Monitor function
FASTENING CURRENT LIMIT
C
U
R
R
E
N
T
TIME / ANGLE
LOW CURRENT LIMIT
HIGH CURRENT LIMIT
FULL SCALE CURRENT