Emerson VSG & VSSG Software Manual page 36

8. Max Speed Detect: Setting for PLC program detection of maximum speed. This setting will not limit
the speed of the VFD. Generally, this setting is useful only when sequencing of multiple devices is
used.
9. Minimum Speed: This is the minimum speed that the PLC will send to the VFD. This is active in
Manual Mode and in Auto Mode.
Adjustment Limit: This is the maximum amount of change in speed per adjustment. If the Calculated Adjust-
ment is greater than the Adjustment Limit value, the PLC output will only change the amount of the Adjust-
ment Limit. If the Calculated Adjustment is less than the Adjustment Limit value, the PLC output will change
the amount of the Calculated Adjustment. The Adjustment Limit is used in conjunction with the Gain to
prevent target overshooting.
10. Gain: This value is factory set to 2.50 but may be set from 0.1 to 99. For VFDs, Gain is a multiplica-
tion factor used in a calculation to determine an adjustment to the speed each set interval. This
interval is defined as the Increase Rate or Decrease Rate. Factory settings for Increase Rate and De-
crease Rate are 2 to 5 seconds.
Manual Button:
Choosing Manual will do the following:
1. The fan Output Mode will remain Manual Mode.
2. Manual Speed: This setting becomes accessible only when the Manual Button is chosen. Enter the
desired speed (%) for the VFD.
Stop Button:
Choosing Stop will remove the fan from Auto and from Manual. The VFD will ramp down to a stop. Note:
The On/Off status of a VFD is based on a nominal speed feedback from the VFD. Therefore, the VFD Status
will display "On" until the drive is near zero speed.
Bypass Button:
Choosing Bypass will remove the fan from VFD speed control. The bypass contactor will be used in lieu of
the VFD.
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