Campbell Scientific SDM-CAN Datalogger to CANbus Interface - Manual (Page 11)

SDM-CAN Datalogger-to-CANbus Interface
• Additional I/O port for signaling to the datalogger that data is available,
e.g. using an interrupt function.
• Has a 9 pin, DCE RS232 port with auto baud rate detection (1200 to
115200) for diagnosis and operating software download.
• Standard operating temperature range (tested), -25ºC to +50ºC. Can be
used over an extended temperature range – contact Campbell Scientific
for details.
• High speed block mode for fast data collection.
• Buffer assisted burst mode for capturing back to back high speed CAN
data.
• Buffer’s support data frame filtering and triggering.
1.2.2 Electrical Specifications
• Power supply range: 7 to 26V DC.
• Optional (switch selectable) galvanic isolation between the datalogger and
the CAN-Bus. The minimum isolation breakdown is 50V – this barrier is
for signal isolation only, i.e. it is not a safety barrier.
• Hitachi H8S,16 bit CPU clocked at 10MHz.
• Uses the latest Philips SJA1000 CAN controller clocked at 16MHz.
• CAN-Bus physical interface using Philips PCA82C251 driver for 1Mbaud
capability, for use in 12V or 24V systems.
• CAN-Bus physical connection conforms to CIA draft standard 102 version
2, 9 pin D connector. (The interface will differ from this standard only
with respect to pin 9, which outputs 5V DC instead of 7-13V DC.)
• A 3 way, unpluggable screw terminal block for CAN High, Low and G
also provided.
• Transmit and acknowledge to CAN-Bus can be disabled by a hardware
jumper for safety reasons, e.g. for in-vehicle, listen only monitoring.
• I/O terminal used for interrupts is pulled low by a 100Kohm resistor and is
driven to 5V via a 1Kohm impedance when an interrupt is pending.
1.2.2.1 Power Consumption
• Typical active current in self-powered, isolated mode with the CAN-Bus
in the recessive state: 70mA. (This is when the SDM-CAN is not
transmitting.)
• Typical active current in self-powered, isolated mode with the CAN-Bus
in the dominant state: 120mA (this is when data is being transmitted from
the SDM-CAN device).
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