Digital inputs
● Optically coupled with a common for all inputs.
● Self powered floating-contact input, or configurable for sinking or sourcing current.
● Sourcing current mode: 24 V internal isolated supply, with positive terminal of
supply at common.
● Sinking current mode: 5 V internal isolated supply, with negative terminal of supply
at common.
Digital outputs
Floating double-throw contacts, maximum contact load rating 1 A at 30 V (AC or DC).
External diode shunt suppression should be used for inductive DC loads, preferably
at the load
Analog inputs
-20 to 20 mA into 50 Ω or
-10 to 10 V Rin = 0.1 MΩ
With alternate insulation up to 10 V
Analog outputs
0/4 to 20 mA into max. 750 Ω, common negative pole, electrically isolated from ground;
freelyconnectable to ground
Termination
SYSCON-based I/O: Terminal strip for braided or solid cable with maximum section of
1.5 mm
2
(16AWG)
Expansion board-based I/O: Screw terminal for shielded or solid cable with a maximum
area of 0.82 mm
2
(18AWG)
Table 3-13
Communication
Serial ports
4 RS232/RS485 ports, e.g. Modbus
Ethernet
● Standard 10/100 BaseT Ethernet with 4 RJ45 connectors e.g. Modbus TCP IP or
OPC
● Optional ESBF board Fiber-optic 100Base FX multimode with ST connection 3 x
RJ45 and 1 x optical
Table 3-14
Gas sample inlet conditions
Sample flow
5 to 100 ml/min (depending on application)
Sample filter size
0.1 to 5 μm with gaseous samples (depending on type of valve)
Minimum sample pressure
35 kPa (5 psig) standard
Maximum sample pressure
200 kPa (29 psig) standard, higher pressure as option
Maximum sample temperature
121°C (250°F) standard; higher temperature as option
Materials in contact with sample
Stainless steel and Teflon; other materials as option
Table 3-15
Combustion gas supply
Combustion gas
● Hydrogen with a purity of 99.999%
● Typical consumption quantity: 2 000 l/month per detector module
Combustion air
● Reference air (< 1 ppm THC, O
2
concentration 20 to 21%). Synthetic air, or supply
through instrument air with catalytic purification (optional).
● Typical consumption quantity: 26 000 l/month
Specifications
Maxum II Reference Manual
98
Manual, 7/2017, 2000596-001
