Applies to: MM420
Yes. This is possible using BiCo technology as follows:
The following example shows 3-wire control with an analogue setpoint, where DIN1 receives the RUN impulse (0 V ® 24 V) and DIN3 receives the STOP impulse (24 V ® 0 V).
P0003 = 3 allows access to level 3 parameters
P0700 = 2 (command source: terminals / BiCo)
P0701 = 99 (BiCo)
P0702 = 99 (BiCo)
P0703 = 99 (BiCo)
- this disconnects all previous connections and allows use of BiCo command connections.
P0848 = 722.2 (this configures OFF3 to DIN3)
P1135 = xxxx s (required (OFF3) ramp down time (usually set to same value as P1121))
P1000 = 23 (main setpoint fixed frequency; additional setpoint analogue: see Note 1)
P1001 = 0.0 Hz (fixed frequency 1 = 0.0 Hz)
P1002 = 0.0 Hz (fixed frequency 2 = 0.0 Hz)
P1016 = 2 (fixed frequency with RUN command)
P1017 = 2 (fixed frequency with RUN command)
P1020 = 722.0 (DIN1 - source of fixed frequency 1)
P1021 = 52.2 (inverter running - source of fixed frequency 2)
With the above settings, the pulse on DIN1 causes the inverter to RUN with FF1 (0.0 Hz) + analogue setpoint. Once the inverter has started this sets status bit 52.2 (inverter running), which then selects RUN with FF2 (0.0 Hz) + analogue setpoint. Therefore the inverter will continue to run after the signal has been removed from DIN1. To stop the inverter, a low pulse must be set on DIN3 which causes an OFF3 and the inverter will stop using the OFF3 ramp down time.
1. On the MM420 it is not usually possible to have two separate RUN commands acting simultaneously. The fixed frequency mechanism, however, allows this. In this case the mechanism is used so that DIN1 selects RUN + FF1 and 52.2 selects RUN + FF2. To enable the RUN commands by this method, fixed frequencies must be a setpoint source. However by setting each fixed frequency to 0Hz and using the analogue setpoint as an additional setpoint (P1000 = 23), the fixed frequencies themselves have no influence on the total setpoint.
2. In the above example, 52.2 is used to give the second RUN command. This leads to the restriction that the inverter cannot be restarted after an OFF3 until Bit 52.2 is no longer high, i.e. the inverter has stopped. Depending on the user application it might be possible to use a different second RUN source to optimise the command sequence (e.g. 53.2 inverter freq > Fmin).