National Instruments NI 9852 - Manual (Page 5)

© National Instruments Corp. 5 NI 9852 Operating Instructions
Each port has two isolated common pins (COM) that are internally
connected to the isolated reference of the module and serve as the
reference ground for CAN_H and CAN_L. Connect the CAN bus
reference ground (sometimes referred to as CAN_V–) to the COM
pin. Each port also has an optional shield pin, SHLD, that can be
connected to a shielded CAN cable. Connecting SHLD may
improve signal integrity and EMC performance in a noisy
environment.
Both of the ports on the NI 9852 require an external power supply
of +8 V to +36 V to operate. Supply power from the CAN bus to
the V
SUP0
pin on CAN0, and the V
SUP1
pin on CAN1.
Pinouts for CAN0 and CAN1 of the NI 9852 are listed in Table 1
and Table 2.