Lou Scannon
Automotive
This is not my field and I do not need to find a solution, only define a space in which a solution exists.
The requirement is to tap into a J1939 CAN, CANOpen, or MODBUS network for example (only one of these capabilities would be required), and read and log certain parameters being transmitted on the bus. Probably no more than 5, including a time stamp. The definition of the parameters would need to be configurable.
The interval of logging should be configurable, say from 1 second to 1000 seconds. Assuming a nominal size for each of the parameters being logged, there should be sufficient memory to store up to 2 million lines of data. Ideally the memory would be removable, such as an SD card or USB drive, for external processing. If a removable memory module is not feasible, then there needs to be an access port such as USB, for downloading stored data and erasing the read/write memory space.
Similarly, configuration should be provided for via serial communication to a PC, e.g. via USB, and host software running on the PC.
As for packaging, I envisage the smallest feasible enclosed module with either a plug-in connector or screw terminals for interfacing to the host system.
If modification to the area network wiring is required to adapt the host to the module then instructions and parts list would be supplied with the module. The host system does not need to be aware of the module's presence (other than incrementing the number of devices on the bus, if necessary). I assume 5 terminals are sufficient, i.e. power, ground, and, e.g., CAN+ & CAN-; possibly a shield as well. If more terminals are required for a particular solution that would not be a problem. External power supply to the module is TBD but will be a common standard such as e.g. 24V or 120VAC.
Logic should include driving an LED and/or built in buzzer to signify successful start up, and annunciate fault conditions (e.g. memory full). Optionally, the LED and/or buzzer can be external, via additional terminals provided for the purpose.
Operation should commence automatically when power is supplied. If memory becomes full, a corresponding alarm will be announced via the LED/buzzer, and either the oldest data will be overwritten, or logging will stop, depending on user configuration. The occurrence of this and other potential error conditions should be stored, and announced to the PC host interface the next time it is connected and used. Naturally, from the host software it will be possible to erase the stored errors.
The mature volumes of this product would run to the 100s or 1000s per year. Hence the required tooling and NRE versus cost to manufacture should take this into account. Life expectancy should be 10 years or more, in an indoor industrial environment. A version hardened for outdoor or engine room exposure would be developed in parallel if needed.
My questions for the group are:
1. Is a suitable PLC a good solution, or would a dedicated PCB design be more cost effective?
2. Given the requirements and volumes, what would be the approximate manufacturing cost, including amortization of NRE?
3. Are there any specific off-the-shelf hardware solutions or partial solutions already available?
4. Is there anything fundamental missing or incompatible in the requirements that makes it difficult to answer these questions?
Many thanks for your patience with my lack of knowledge in this subject area, and for your feedback.
"Schiefgehen wird, was schiefgehen kann" - das Murphygesetz
The requirement is to tap into a J1939 CAN, CANOpen, or MODBUS network for example (only one of these capabilities would be required), and read and log certain parameters being transmitted on the bus. Probably no more than 5, including a time stamp. The definition of the parameters would need to be configurable.
The interval of logging should be configurable, say from 1 second to 1000 seconds. Assuming a nominal size for each of the parameters being logged, there should be sufficient memory to store up to 2 million lines of data. Ideally the memory would be removable, such as an SD card or USB drive, for external processing. If a removable memory module is not feasible, then there needs to be an access port such as USB, for downloading stored data and erasing the read/write memory space.
Similarly, configuration should be provided for via serial communication to a PC, e.g. via USB, and host software running on the PC.
As for packaging, I envisage the smallest feasible enclosed module with either a plug-in connector or screw terminals for interfacing to the host system.
If modification to the area network wiring is required to adapt the host to the module then instructions and parts list would be supplied with the module. The host system does not need to be aware of the module's presence (other than incrementing the number of devices on the bus, if necessary). I assume 5 terminals are sufficient, i.e. power, ground, and, e.g., CAN+ & CAN-; possibly a shield as well. If more terminals are required for a particular solution that would not be a problem. External power supply to the module is TBD but will be a common standard such as e.g. 24V or 120VAC.
Logic should include driving an LED and/or built in buzzer to signify successful start up, and annunciate fault conditions (e.g. memory full). Optionally, the LED and/or buzzer can be external, via additional terminals provided for the purpose.
Operation should commence automatically when power is supplied. If memory becomes full, a corresponding alarm will be announced via the LED/buzzer, and either the oldest data will be overwritten, or logging will stop, depending on user configuration. The occurrence of this and other potential error conditions should be stored, and announced to the PC host interface the next time it is connected and used. Naturally, from the host software it will be possible to erase the stored errors.
The mature volumes of this product would run to the 100s or 1000s per year. Hence the required tooling and NRE versus cost to manufacture should take this into account. Life expectancy should be 10 years or more, in an indoor industrial environment. A version hardened for outdoor or engine room exposure would be developed in parallel if needed.
My questions for the group are:
1. Is a suitable PLC a good solution, or would a dedicated PCB design be more cost effective?
2. Given the requirements and volumes, what would be the approximate manufacturing cost, including amortization of NRE?
3. Are there any specific off-the-shelf hardware solutions or partial solutions already available?
4. Is there anything fundamental missing or incompatible in the requirements that makes it difficult to answer these questions?
Many thanks for your patience with my lack of knowledge in this subject area, and for your feedback.
"Schiefgehen wird, was schiefgehen kann" - das Murphygesetz
