Ziton A70E-2 | Addressable Conventional Zone Interface | DIN Rail, Loop Powered

FAQs

How many conventional detectors can be connected to the A70E-2?

The A70E-2 can support different quantities depending on the operating mode and detector type. In Normal or Head-out operating modes, up to 32 Ziton 610, 620, 630 series detectors or GST DC-91 series conventional devices can be connected to a single interface module. In Intrinsically Safe mode for hazardous area applications, up to 15 Hochiki IS devices can be connected (requiring a GBX2000 galvanic isolator). The module appears as a single addressable device on the loop regardless of how many conventional detectors are connected to it.

What are the three operating modes and when should each be used?

The A70E-2 offers three operating modes selectable via the Mode DIP switch. Normal mode (SW1 and SW2 OFF) provides standard conventional detector operation with open and short circuit monitoring using a 3.9kΩ EOL resistor – this is the most common configuration for standard conventional zones. Head-out mode (SW1 OFF, SW2 ON) enables detector removal monitoring when using Z6x0-3 detectors with Z6-BS5 bases containing a Schottky diode, maintaining operation of other zone devices when a detector is removed. Intrinsically Safe mode (SW1 ON or both SW1 and SW2 ON) interfaces with certified IS detectors for hazardous areas using an 8.2kΩ EOL resistor. Note that it’s not possible to operate in both IS and head-out mode simultaneously.

Can the A70E-2 be powered directly from the loop?

Yes, the A70E-2 is fully loop-powered as standard, drawing its operating power directly from the ZP addressable loop at 18-20.5V pulsed. Loop-powered operation consumes 8.3mA quiescent and up to 24.6mA in alarm conditions. However, in systems where numerous interface modules are installed or current requirements are excessive, the A70E-2 can alternatively be powered from an external EN54-4 compliant 24VDC power supply (19-30VDC). External power selection is configured using jumper J1. When externally powered, the module draws 7.3mA quiescent and up to 36.6mA in alarm from the external supply, with only 1.5mA drawn from the loop.

How does head-out detection work?

Head-out detection allows the A70E-2 to monitor when a detector is removed from its base while maintaining operation of all other devices in the zone. This requires Z6x0-3 series detectors installed on Z6-BS5 bases that include a series Schottky diode, or other detectors with a series supply diode fitted to the base. When configured in head-out mode (Mode DIP switch: SW1 OFF, SW2 ON) and using a 3K9 resistor, the interface monitors the circuit configuration to detect head removal. This is valuable for maintenance purposes as it alerts the system when a detector has been removed without disabling the entire zone.

What is the difference between the 3.9kΩ and 8.2kΩ end-of-line resistors?

The A70E-2 uses different end-of-line (EOL) resistor values depending on the type of devices connected and the operating mode. The 3.9kΩ (3K9) EOL resistor is used with standard conventional devices in Normal and Head-out operating modes – this is supplied with the unit and provides open and short circuit fault monitoring for typical conventional detector zones. The 8.2kΩ (8K2) EOL resistor is specifically required when operating in Intrinsically Safe mode with certified IS detectors for hazardous area applications. The different resistance values enable the module to correctly monitor circuit integrity for the specific electrical characteristics of standard versus intrinsically safe detection equipment.

How is the address set on the A70E-2?

The A70E-2 uses a seven-segment DIP switch for address configuration using binary coding. Each switch has a decimal value: switch 1 = 1, switch 2 = 2, switch 3 = 4, switch 4 = 8, switch 5 = 16, switch 6 = 32, and switch 7 = 64. The device address is calculated by adding the values of all switches set to ON. For example, to set address 007, switches 1, 2, and 3 should be ON (1 + 2 + 4 = 7) with all other switches OFF. This allows any address from 1 to 127 to be configured, with each conventional zone taking one addressable loop address.

What do the LED indicators show?

The A70E-2 features two LED indicators for status monitoring. The red Alarm LED flashes when the conventional zone is in fire alarm condition – once registered by the panel, this alarm output is maintained until the system is reset. The yellow Fault LED flashes when the conventional zone has a fault condition (open or short circuit wiring fault), and this LED is non-latching so it immediately reflects current fault status. Additionally, the yellow Fault LED will double-flash to indicate a power supply fault, such as when jumper J1 is left out or when external power is removed while J1 is set to the external power position.

Can multiple A70E-2 modules be used on the same loop?

Yes, multiple A70E-2 modules can be installed on the same ZP addressable loop. The Ziton protocol supports up to 127 addressable devices per loop, which can include detectors, manual call points, and interface modules. With external power supplies, up to 127 conventional zone interface modules could theoretically be installed on a single loop, each monitoring its own conventional detector zone with a unique address. This enables large conventional fire alarm systems to be integrated into a single addressable control panel, providing centralized monitoring and control of all conventional zones throughout a facility.