Description
Indication module of CNG dispenser
Can be used in CNG dispenser together with control unit RAR-ECM.
Indication type – 7 segment.
Digits amount – 8, 8, 6.
Digits of decimal part – 2.
Type of displayed values – decimal (float) digits. (Combination of decimals, integers and chars possible to be displayed by request using custom firmware.)
Communication interface – CAN-bus. (RS-485 available by request).
Power supply – 24vdc, 3W.
Temperature range – -40°С to 60°С.
Light – yes.
Bootloader – yes. Allows to update firmware from control unit without dispenser disassembly.
Moisture protection – varnish.
Warranty period – 24 month.
OEM is possible.
Price might be reduced on batch orders.
Communication protocol
Two positional toggle switch (0 and 1) exists on the back side of indication module that used to set bus address of device. Two devices can be used on the CAN bus same time.
Data to be displayed provided by control unit using CAN bus.
Two packets used to display floats:
- packet with address 0x20 or 0x40 (depending on toggle switch position) used to display two upper rows (8 digits each row) of data. Two floats 4 bytes each. 8 bytes packet.
- packet with address 0x21 or 0x41 (depending on toggle switch position) used to display lower row of data (6 digits row).
That was implemented due the typical work flow of indication module in CNG dispenser when upper two rows used to display cost/volume of charged fuel while lower one used to display fuel price per volume unit.
By request communication protocol can be customized.
Packet examples
To display following values with toggle switch in position 0:
following CAN packet need to be sent:
020#8e0359498e03d948
021#290ef345
Here:
- 0x20 и 0x21 – packet address;
- 8e035949 – float view of 888888.88 (0x4959038e) in LSB.
- 8e03d948 – float view of 444444.44 (0x48d9038e) in LSB.
- 290ef345 – float view of 7777.77 (0x45f30e29) in LSB.
Same with toggle switch in position 1:
040#8e0359498e03d948
041#290ef345
Float presentation in 32bit view might be found here:
but usually it is not required due to float type supported natively by most programming languages.