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R2 CAN Installation manual
7 The IRMA gateway as an interface adapter
The IRMA gateway serves as an adapter between the CAN interface and other interfaces.
Depending on the IRMA gateway version, the following interfaces are possible:
• IBIS interface with unit IRMA-Gateway-4-IBIS, see section 7.1.2 , p. 40
• RS485.2 interface with unit IRMA-Gateway-4-RS485.2, see section 7.1.3, p. 40
• J1708 interface with unit IRMA-Gateway-3-J1708, see section 7.1.4, p. 41
• RS232 interface with unit IRMA-Gateway-3-RS232
• switching outputs with unit IRMA-Gateway-0-OSW4
7.1 Door signal input and on-board computer connection
The cable for connecting the IRMA gateway with the door signal inputs and the on-board
computer is connected to connector "V".
The door signal input provides the information on the door status, i.e. whether the door is
open or closed. Passenger counting is to be interrupted while the door is closed! For this
purpose it is necessary to have the door signal available without delay.
Table 6: Logical evaluation of the door signals
Door open/closed
Voltage level for door signal logically positive or negative
logically positive logically negative
Door open (including door
opening and closing
+9 ... +32 V DC 0 ... +6 V DC
"Logically negative" is the preferred alternative if the sensor is to count passengers also
when no voltage is applied at the door signal input (e.g. if the ignition of a bus is switched
off). The door contact logic is configured in the sensor (section 8.2, p. 47, "Door Polarity").
The IRMA gateway offers two options for evaluating the door signals which can be
activated by using different cable sets:
1. Potential-free switch - Here an internal voltage (generated in the IRMA gateway) is
applied and the switching status evaluated accordingly.
2. Evaluation of voltage levels - Here voltages from the vehicle are evaluated, e.g. from the
door control.
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