Stulz EC Tower ECD 91 - 3. Product description; 3.1 Types of connection

146 EN/01.2019/G22 © STULZ GmbH – all rights reserved
ec tower technical manual
3. Product description
The InterfaceIIIk is an expansion module for the X/Y remote control bus of indoor units from Mitsubishi
Heavy Industries. It connects the X/Y remote control bus to the control unit of the building management sys-
tem (BMS).
The InterfaceIIIk is integrated in the X/Y remote control bus as an additional participant. It acts as an addi-
tional wired remote control. The InterfaceIIIk can control up to 16 indoor units.
Depending on which program is selected, the InterfaceIIIk reads a 010 V DC signal at arriving at the X3S
analog input and forwards the value to the indoor unit as a setpoint (see “3.1.1 Analog input“ on page 146).
Various functions are available, see “4. InterfaceIIIk functions“ on page 149.
3.1 Types of connection
3.1.1 Analog input
A 010 V DC signal at the X3S analog input determines the temperature or frequency setpoint, depending
on which program is selected. The DC signal uses the ground connection X3-(-RV) as a reference.
The DC signal is analyzed proportionally at the X3S analog input. The referenced value tables are pro-
gram-dependent and described together with the corresponding program. All programs feature open-circuit
protection.
3.1.2 Digital inputs
The assignment of digital inputs varies depending on the program, and largely determines the behavior of the
selected program.
All digital inputs are electrically isolated. The input voltage range is 20VDC to 130VDC or 24VAC to
230VAC. The current status of the digital inputs is indicated by LED1 to LED6.
3.1.3 Digital outputs
Each of the three digital outputs X4a-K1, X4b-K2 and X4c-K3 is a voltage-free contact. They have a load
capacity of 230VAC/130VDC, 0.5A. The switching state of the respective relay is indicated by LED11,
LED12 and LED13 . A lit LED indicates that the corresponding relay is energized and the contact is closed.
A relay’s switching state changes when the condition for a signal is met. You can configure which signal is
emitted at each output using DIP switch S22, depending on the program. See descriptions of the individual
programs for more details.
3.1.4 X/Y remote control bus
X1X and X1Y are the connection terminals of the X/Y remote control bus. This bus enables communication
between the remote control, the indoor unit, and the InterfaceIIIk.
The X/Y remote control bus is designed as a power bus with reverse polarity protection, and supplies the
InterfaceIIIk with the required operating voltage.