Sequential Starting for VSDs
Many applications use two or more motors for operation, but sometimes some of the motors need not to start after some time interval after another motor (sequential control with some delay). Such a Leader-Follower (Master/Slave) Start and Stop application is thus where two or more VSDs are linked to maintain a predetermined order at which the motors are forced to Start and Stop. Typically, the first drive is configured as the “Leader” or “Master” and the subsequent drive/s that follow the master are referred to as the “Slaves” or “Followers”.
To use one VSDs Running State (VSD 1 = Leader VSD) as a signal to specify another VSDs Start-up (VSD 2 = Follower VSD), please connect the VSDs and set the required parameters as follows:
Connections:
- Connect Leader VSD TA2 with Follower VSD DI1
- Connect Leader VSD TC2 with Follower VSD COM
Please Note: For Smaller Drives with only one set of Relays (TA-TB-TC), use the TA2-TB2-TC2 Relay parameter settings.
Parameter Settings VSD2 (Follower):
- Set b0-02 = 1 (Terminal Control)
- Set b3-00 = 1 (DI1 Forward Run) – this is the default value for b3-00
- The Start can be delayed by setting b3-15 = DI1 ON delay time in seconds (max 3000s)
- The Stop can be delayed by setting b3-16 = DI1 OFF delay time in seconds (max 3000s)
Parameter Settings VSD1 (Leader):
- Set b4-03 = 2 (Frequency Inverter Running)
- Alternative to the above, the following Relay States can also be used:
- b4-03 = 7 (Frequency Upper Limit Reached)
- b4-03 = 19, 20 or 21 (Reaching a Pre-defined Frequency)
- b4-03 = 22 or 23 (Reaching a Pre-defined Current)
- Alternative (or additional) delay options than the Follower VSD Digital delays, the Leader VSD Relay output can also be delayed by setting the Relay On or OFF delay time by setting parameters:
- b4-14 = Relay 2 ON delay time in seconds (max 3000s)
- b4-15 = Relay 2 OFF delay time in seconds (max 3000s)
