BIG ASS FANS Basic 6 Manuel D'installation page 37

Daisy chaining
WARNING: Wait three minutes after disconnecting before servicing!
The following parameter changes and diagram enable daisy chaining of multiple fans. The first fan provides a
start/stop contact and 0–10 VDC analog speed reference for the first downstream VFD, which then provides a
new start/stop contact and 0–10 VDC analog speed reference for the following downstream VFD. This preferred
method of linking VFDs ensures minimal command signal loss in larger multi-fan systems.
Assertion Level Switch (ALSW)
The VFD ships with the onboard digital I/O configured for Sourcing (PNP) operation. Terminal 4 provides +15
VDC to be used as a supply voltage for user-supplied switches and accessories. For this three-wire daisy
chaining application, the downstream VFDs must be switched to Sinking (NPN) operation. Terminal 4 will then
provide a DC common connection and allow the analog signal and start/stop signal to share that common. The
Assertion Level Switch above terminal 4 must be switched from (+) to (-) on all downstream VFDs for proper
daisy chaining operation prior to powerup, parameter changes, and operation.
Parameter changes (for first VFD)
Parameter Description
Relay Output Function
Change from "0" for None to "1" for Run
TB-30 Output
Change from "0" for None to "1" for
0–10 VDC output (scaled to drive output
frequency)
TB-30 Scaling Frequency
Change to equal the frequency setting
of P103 Maximum Frequency
Speed at Max Signal
Change to equal the frequency setting
of P103 Maximum Frequency
Note: Depending on the AWG and distance of the low voltage wiring, the downstream fans may run
slightly slower than the lead fan. If this occurs, P161 Speed at Max Signal can be used to introduce a
minor command reference overshoot to compensate for the analog voltage drop. At each downstream
fan (beginning with the first), adjust the value of P161 up in 0.1–0.2 Hz increments until the fan's output
frequency matches that of the lead fan.
WWW.BIGASSFANS.COM © 2018 DELTA T LLC
Parameter changes (for downstream VFDs)
Parameter Description
Assertion Level
Change from "2" for High to "1" for Low
Start Control Source
Change from "0" for keypad operation
to "1" for terminal strip
Standard Reference Source
Change from "0" for keypad operation
to "1" for 0–10 VDC analog input
operation
ALL RIGHTS RESERVED.
33