NI_GPIB_ENET_Py3

Python3 scripts to set up and communicate with the obsolete NI GPIB-ENET (not GPIB-ENET/100 OR 1000).

Set up IP address

The NI GPIB-ENET uses the obsolete Reverse-ARP(RARP) protocol for setting up the IP address (when switch-5 is OFF). The protocol works on Layer 2 (Data link layer), which means we cannot read/write the raw packets via Python3's builtin module socket on Windows. But it's doable on Linux. Please refer to https://www.cloudshark.org/captures/c6729d0fc558 for the details of the RARP request/reply packets.

Example RARP reply packet

For example, in my case

Item	MAC Addr	IP	IP(hex)
PC	90-B1-1C-9B-B1-E9	192.168.3.1	C0 A8 03 01
GPIB-ENET	00-80-2F-FF-09-94	192.168.3.2	C0 A8 03 02

The RARP reply packet to be sent to GPIB-ENET

00 80 2F FF 09 94|90 B1 1C 9B B1 E9|80 35|00 01|08 00|06|04|00 04|90 B1 1C 9B B1 E9|C0 A8 03 01|00 80 2F FF 09 94|C0 A8 03 02 

• Target MAC (GPIB-ENET) 00 80 2F FF 09 94
• Sender MAC (PC) 90 B1 1C 9B B1 E9
• Protocol (RARP) 80 35
• Hardware (Ethernet) 00 01
• IPv4 08 00
• Hardware size 06
• Protocol size 04
• Opcode (reply) 00 04
• Sender MAC 90 B1 1C 9B B1 E9
• Sender IP C0 A8 03 01
• Target MAC 00 80 2F FF 09 94
• Target IP C0 A8 03 02

Windows

Please check libpcap for sending the reply packet in Python3. Alternatively, some traffic generators can be found on WireShark Wiki. I used the free Packet Player from Colasoft to convert the HEX text to *.cap then sent it.

Linux

Please check the documentation for socket on how to send the reply packet in Python3. Hint: use socket(AF_PACKET, SOCK_RAW)

Store IP address

When the IP assignment is finished, the READY LED indicator will become steady. If you want to retain the IP address in the future power cycles, you may turn off the NI GPIB-ENET and turn switch-5 to ON.

Communication

The low-level libnienet.py was originally written by Robert Jordens. I modified it to work with Python3.

An simple high-level wrapper (GPIBENET) over libnienet.py can be found in example_simple_wrapper.py. Only read/write/query have been implemented. All the input/return 'string's were kept as bytes, so please encode or decode them per your needs.

Example device GPIB address is 16,

from example_simple_wrapper import GPIBENET
GPIB_ENET_ADDR = '192.168.3.2'
DEV_GPIB_ADDR = 16
dev = GPIBENET(GPIB_ENET_ADDR, DEV_GPIB_ADDR)
print(dev.query(b'*IDN?').encode())
# OUTPUT:
# KEITHLEY INSTRUMENTS INC.,MODEL 2010,0772543,A10  /A02

The scripts have met my needs, so I lost the motivation for further improvement. But you are more than welcome to fork/modify it.