iSMA-B-FCU Hardware User Manual
www.ismacontrolli.com
DMP242en | 1st Issue rev. 3 | 02/2022
page 24 of 53
Figure 20. O1-O3 digital outputs, examples of conenctions
O4 HTG Relay
The iSMA-B-FCU device is equipped with relay output, which in the FCU application is
dedicated to an external heater. This relay is separated from the rest of the control
circuit. Current consumption cannot exceed 10 A with 250 V AC power supply. The figure
below presents the way of connecting.
WARNING!
HTG relay voltage is always limited to 250 V AC, irrespectively of the power
supply version of the FCU controller.
WARNING!
This digital output is equipped with a separate circuit with
10 A
relay. This
circuit requires using external fuse protection up to
10 A.
The current higher than
10 A
may permanently damage device and cause danger to the user and to the
equipment!
