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5.0 IRMA Communication System

Communication between the on-board computer and the analysers with the J1708 interface is not described in this documentation, but in the Iris documentation "Universal J1708-IRMA-Protocol". Communication between the on-board computer and the analysers with IBIS, RS-485 and RS-232 interfaces takes place using the data records defined in the VDV 300 (IBIS) guideline.

Iris-GmbH has added further data records to these data records in order to make working with the IRMA passenger counting system more convenient. In addition, all call data records of the on-board computer have been extended by a door address in order to differentiate between several doors. Call data records without door address are not answered by IRMA.

The table lists all available data records:

The call data record DS0801 allows polling of the software version of the analyser. Other than the VDV 300, however, the response data record can be 8 characters long.
The call data record bPH is not included in the VDV 300. The response data record can be 8 characters long. It is used to poll as to how the configuration data (door addresses etc.) were written into the analyser.
The call data records DS080 and DS081 usually are not required for the function of the IRMA passenger counting system, as information on the door status (doors open or closed) are gained by a door contact. If the call data record DS080 is sent from the on-board computer, it is answered only formally with DS181 by IRMA.
The call data record DS084 is used by the on-board computer to determine the status of the passenger counting system. IRMA fault: If, with the door open, a fault is detected by the auto-diagnostic function of the analyser, it sends bS3 as a response data record. This can happen, if, for example, a sensor is missing or defective. If a fault is signalled by the response data record bS3, all further call data records of the same address are also followed by the response data record bS3, until the fault has been repaired and the power supply of the passenger counting system was switched off and on again. IRMA sabotaged: When at a door at least one sensor (precisely speaking the active component of the sensor) has been covered over the entire period of door opening, the analyser will transmit the response data record bS4 after the next closing of door. This response data record will only be transmitted when the doors are closed, relating only to a possible sabotage during the period of last door opening. IRMA fault and sabotaged: If both cases occur at the same time, the analyser will transmit the response data record bS3 (IRMA fault) as a response to the status polling.=> The call data record DS084 must not be used with analysers with an RS-485 interface operated in half-duplex mode. In this case, the call data record bRH must be used (also refer to the table below).
If IRMA receives the call data record DS082, the separate counts for boarding and alighting passengers are transferred from the internal count register into an output buffer. IRMA acknowledges the call of DS082 with the data record DS181. This procedure is repeated if IRMA again receives the call data record DS082.
Upon receipt of the call data record DS083, the counts contained in the output buffer are sent to the on-board computer by means of the response data record DS183 (as hex code according to VDV 300). This procedure can also be repeated several times. At a time with the receipt of DS083, the count registers for boarding and alighting passengers are reset to zero. The output buffers than still include the most recent count values for boarding and alighting passengers. The output buffers are updated only with the next call data record DS082. The data records DS082 and DS083 may not be sent as long as the doors are open, as otherwise errors in the count results can occur. If a door is opened and closed several times at the same stop, the count results are added and can be retrieved in the way described above after leaving the stop.
The call data record bWH is not included in the VDV 300. The on-board computer can use this call data to poll the current door status from the analysers, i. e. which door has been recognized as open or closed, respectively, by the analysers. This data record can also be used to check the door contact.
The call data records bYH and bZH are not included in the VDV 300. The call data record bYH activates the test function "Simulation of passenger change" in the analyser, and the call data record bZH deactivates it.The test function serves the transmission of defined counts from the analyser to the on-board computer, without any sensors having to be connected to the analyser, or without a passenger change having to take place.

Algorithm of the "counts" of the test function "Simulation of passenger change"

The sum of boarding and alighting passengers at each door is 100. The number of boarding passengers is reduced by 1 and the number of alighting passengers increased by 1 by each opening of the door.

"Counts" in the analyser

Out

with active test function with the door closed

after the 1^st opening of the door

after the 2^nd opening of the door

after the 3^rd opening of the door

after the 99^th opening of the door

after the 100^th opening of the door

after the 101^st opening of the door

0
100
99
98

2
1
0

0
0
1
2

98
99
100

Notes on the test function

The test function is deactivated also by a short switching-off of the power supply of the analyser.
If in an analyser for 2 doors the test function is activated only for one of the two door addresses, no "correct" counts can be polled from the other door address.

Call data records of the on-board computer / Meaning			Response data records of the analyzer / Meaning
DS0801	bVH	Polling of software version	DS1801	bVX	Transmission of software version
-	bPH	Polling of parameterization	-	bPX	Transmission of the way of setting parameters
DS080	bTH	Door was opened	DS181	bF	Acknowledgement and identification
DS081	bMH	Door was closed	DS181	bF	Acknowledgement and identification
DS084	bSH	Polling of the device status (Not possible with RS-485 in half-duplex mode)	DS184		Transmission of the device status
				bS0	IRMA in order, no measuring result available
				bS1	IRMA in order, new measuring result available
				bS2	IRMA in order, measurement not yet finished or counts not yet transferred into the output buffer
				bS3	IRMA fault
				bS4	IRMA sabotaged
-	bRH	Polling of the device status (Possible only with RS-485 in half-duplex and full-duplex mode)	-		Transmission of the device status
				bR00	IRMA in order, no measuring result available
				bR01	IRMA in order, new measuring result available
				bR02	IRMA in order, measurement not yet finished or counts not yet transferred into the output buffer
				bR03	IRMA fault
				bR04	IRMA sabotaged
DS082	bFH	Travel started	DS181	bF	Acknowledgement and identification
DS083	bEH	Polling of counts	DS183	bEEAA	Transmission of the counts · EE = 2 digits for the number of boarding passengers · AA = 2 digits for the number of alighting passengers
-	bWH	Polling of door status	-		Transmission of the door status (door open or door closed)
				b0	Door is open or moving
				b1	Door is closed
-	bYH	Activation of the test function "Simulation of passenger change"	DS181	bF	Acknowledgement and identification
-	bZH	Deactivation of the test function "Simulation of passenger change"	DS181	bF	Acknowledgement and identification

H = door address