Carel Heez Technical Leaflet page 55

ENG
Fig. 3.p
Leakage current
The drive is designed to produce minimum leakage current, nonetheless leakage current depends on the length and
type of motor cable, the motor, the effective switching frequency, the type of earth connection used and the type of
RFI filter installed, and therefore may exceed 1 mA.
Compressor protection safety digital input
Connect the two "Safe Torque Off" digital safety input terminals to the normally-closed voltage-free contact of a safety
device, such as a maximum pressure switch (safety device, see the connection diagram). When the contact is open,
drive operation is interrupted. If the Safe Torque Off feature is not used, the two safety digital input terminals must be
short-circuited to enable correct operation of the controller.
Serial network connection
For the serial connection use a shielded three-wire cable. For very long networks, add a ¼ W 120 Ω resistor between the
Tx/Rx- and Tx/Rx+ terminals on the last controller or device connected, to avoid possible communication problems.
To ensure conformity to the EMC directive it may be necessary to use a ferrite core (for example, Fair-Rite 2631540002)
fitted immediately before the drive terminal, winding the three wires (excluding the cable shield) around this.
BUILDING
MANAGEMENT SYSTEM
RS485
TX / RX GND
J9 J9
TX/ RX GND BMS TX / RX GND BMS
Schermo/Shield
R = 120 Ω
Fig. 3.q
Heez +050002745 rel. 1.2 - 16.11.2021
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