PEAK-System Forum

I have been experimenting with PEAKCAN-USB and PCANBasic to make a data capture product and have managed to get reasonable results. I have proved the concept and am considering what limitations there might be with different hardware such as PEAKCAN-USB and the Pro version. The nodes will only be standard CAN devices transmitting standard frames, FD is not important.

Some questions I can't seem to find definitive answers to are:
1. What is the size of the receive buffer in the different software packages?
ie. I want to estimate how quick it will fill up and how often I should read it.
2. Is PCANBasic capable of running two or more PEAKCAN-USB devices simultaneously?
Or do I need to use the RP1210 API.
3. What are the advantages of using the RP1210 API?

I just found one answer: 32,768 messages per CAN channel is the buffer size for Tx and RX.

But that reminds me of another question - how many nodes can you connect to one channel?
Will it be up to the technical max of CAN, ie 127 (assuming bas traffic is not saturated) or is there a software limit in PCANBasic?

Hello mark32,

mark32 wrote:1. What is the size of the receive buffer in the different software packages?

Each channel has a receive queue that can store up to 32.768 messages.There is no send queue. Messages sent through CAN_Write will be directly passed to the driver for writing.

mark32 wrote:2. Is PCANBasic capable of running two or more PEAKCAN-USB devices simultaneously?

Yes, PCAN-Basic can handle several channels of several PCAN-Devices at the same time. The following list shows the PCAN-Channels that can be connected per PCAN-Device:

• PCAN-ISA: 8
• PCAN-Dongle: 1
• PCAN-PCI: 16
• PCAN-USB: 16
• PCAN-PC-Card: 2
• PCAN-LAN: 16

mark32 wrote:3. What are the advantages of using the RP1210 API?

Here some difference points between the APIs
RP1210:

• It allows using two protocols, raw CAN and J1939.
• You need to buy a license for use the API in your own application (single license).
• You need to buy a special developer license if you want to sell your RP1210 application (developer license)
• A RP1210 channel can be connected several times simultaneously.
• Since RP1210 is a "recommended practice" for CAN development, your application will be capable to use hardware from different companies, as long as their devices support RP1210.

PCAN-Basic:

• It is for free
• You can develop software for own use or for sell
• It work only with raw CAN
• A PCAN-Basic channel can be initialized only once, i.e. a channel cannot be connected from two different applications simultaneously.
• It works only with PEAK hardware

mark32 wrote:how many nodes can you connect to one channel?

A PCAN channel is itself a node. So, your question is about the CAN environment to use. PCAN-Basic concerns only, that the maximum amount of simultaneously connected channels per device is 16 (in case of PCAN-USB, for example), and that each of then can be used only by one application simultaneously.

I think my understanding of PCAN channels and nodes is a little confused after reading the last answer. "A PCAN channel is itself a node" - is this a node with respect to the PCANBasic API or the raw CAN bus?

From the rest of the answer my interpretation is that PCANBasic can connect to up to 16 devices (ie, PCAN-USBs) and handle CAN messages from each simultaneously. What I was trying to ask was can each of the 16 devices manage multiple CAN nodes (in my case sensors) connected to each device bus and is the limit based on individual bus loading?

Or to put it another way: if I used one PCAN-USB device could I connect a hundred of my sensors to the CAN bus assuming the bus loading is OK?

Hello,

mark32 wrote:"A PCAN channel is itself a node" - is this a node with respect to the PCANBasic API or the raw CAN bus?

This is with respect to the CAN bus. Supposing the CAN bus supports up to 128 nodes, then each PCAN device (channel) connected to that CAN bus represents a node.

mark32 wrote:Or to put it another way: if I used one PCAN-USB device could I connect a hundred of my sensors to the CAN bus assuming the bus loading is OK?

Yes.