Multi-Board Workflows

Multiple HMCLS boards can collaborate in real time over an Ethernet network using the NET command block and the event flag system.

Network Topology

All boards must be on the same Ethernet subnet, each with its own address:

Board	Example IP
Board A	192.168.1.21
Board B	192.168.1.22
Board C	192.168.1.23

On a network with a DHCP server, each board receives its own address at boot; read it on the device screen. To keep the same addresses from one session to the next, reserve them in your router (DHCP reservation). Without a DHCP server, every board falls back to the same address (192.168.1.11): do not connect several boards to the same segment in that case.

Triggering Another Board

Board A can raise a flag on Board B by sending a NET command:

Board A loop — signal Board B

NET command "192.168.1.22" "FLAG SET 1"

Board B's script waits for the flag:

Board B loop — wait for signal from A

if flag (consume) 1:
  LED1 on

Python Example

You can coordinate boards from a Python script on the PC. The example below makes this PC the owner of both boards (so that it receives their messages), starts the acquisition on both, then signals Board B when Board A reports a spike on channel 0.

multi_board_trigger.py

import socket

MY_IP = "192.168.1.50"           # the IP of this PC
IP_A = "192.168.1.21"
IP_B = "192.168.1.22"
CMD_PORT = 55152
TEXT_PORT = 55153

tx = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)

def send_cmd(ip: str, text: str) -> None:
    tx.sendto(text.encode(), (ip, CMD_PORT))

# Listen first: replies, `say` messages and events come back on port 55153
rx = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
rx.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
rx.bind(("0.0.0.0", TEXT_PORT))
rx.settimeout(30.0)

# Take both boards and start the acquisition (SETUP is only needed if the board asks for it)
for ip in (IP_A, IP_B):
    send_cmd(ip, f"DEST {MY_IP}")
    send_cmd(ip, "START")
print("Acquisition started on both boards.")

print("Waiting for a spike on Board A channel 0...")
try:
    while True:
        data, addr = rx.recvfrom(512)
        for line in data.decode(errors="replace").splitlines():
            if addr[0] == IP_A and line.strip() == "spike ch0":
                print("Spike detected on Board A — triggering Board B.")
                send_cmd(IP_B, "FLAG SET 1")
                raise SystemExit
except socket.timeout:
    print("Timeout: no spike detected within 30 s.")

Board A's Loop script must send a message when a spike is detected, so that the PC can catch it (flag 33 + channel is raised by spike detection):

Board A Loop — announce spike on channel 0

if flag (consume) 33:
  say "spike ch0"

Board B's Loop script reacts to flag 1:

Board B Loop — react to trigger from PC

if flag (consume) 1:
  LED2 on   // yellow: triggered

See NET Relay and Multi-Board Flag Coordination for the protocol-side details.