How to connect a Cognex camera to a Doosan robot over TCP

thijs · September 2, 2026, 12:16am

Based on contributions by How-to, salvacmp.

Doosan robots can read results from a Cognex vision system directly over a TCP socket, without any extra hardware — the robot connects to the camera’s native command interface, logs in, triggers a capture, and reads back the values from a cell in the camera’s job.

What you need

A Doosan robot
A Cognex camera, configured with a job that writes results to a table cell
The camera set to Online Mode (triggering only works in this mode)
The Doosan and the Cognex camera on the same IP subnet

Steps

1. Configure the connection parameters

port = 10000
ip = "192.168.137.10"

Set ip to your camera’s actual IP address, and make sure the Doosan controller is on the same subnet.

2. Open a TCP connection to the camera

socket = client_socket_open(ip, port)

3. Log in

After connecting, the camera sends a welcome message and then asks for a username and password:

receive = client_socket_read(socket, -1, -1)[1].decode()
client_socket_write(socket, "admin\r\n".encode())   # username + carriage return, newline

### asked for a password ###
receive = client_socket_read(socket, -1, -1)[1].decode()
client_socket_write(socket, "\r\n".encode())        # empty password + carriage return, newline

A successful login returns a logged-in message:

receive = client_socket_read(socket, -1, -1)[1].decode()

4. Trigger the camera

This only works if the camera is in Online Mode.

client_socket_write(socket, "SE8\r\n".encode())
wait(3)

triggerstatus = client_socket_read(socket, -1, -1)[1].decode()[:-2]

if triggerstatus != "1":
    tp_log("Trigger failed: " + str(triggerstatus))
    return 0

5. Read a cell value

Cell names follow the pattern GVxyyy: x is the column letter, yyy is the row number. For example GVC019 reads cell C19.

cel_data = "GVC019"
client_socket_write(socket, (cel_data + "\r\n").encode())
getvaluestatus, rec, _empty = str(client_socket_read(socket, -1, -1)[1].decode()).split("\r\n")

if getvaluestatus == "1":
    rec = str(rec).split(",")
else:
    tp_log("GetValue failed: " + str(getvaluestatus))

6. Close the connection

client_socket_close(socket)

Full code

Combining the steps above into one reusable function:

def get_data_from_cognex(cel_data):
    ### configuration, adjust as needed ###
    port = 10000
    ip = "192.168.137.10"

    ### connect to the camera ###
    socket = client_socket_open(ip, port)

    ### camera sends a welcome message and asks for username and password ###
    receive = client_socket_read(socket, -1, -1)[1].decode()
    client_socket_write(socket, "admin\r\n".encode())  # username + carriage return, newline

    ### asked for a password ###
    receive = client_socket_read(socket, -1, -1)[1].decode()
    client_socket_write(socket, "\r\n".encode())  # empty password + carriage return, newline

    ### logged-in message ###
    receive = client_socket_read(socket, -1, -1)[1].decode()

    ### trigger the camera, only works in Online Mode ###
    client_socket_write(socket, "SE8\r\n".encode())
    wait(3)

    triggerstatus = client_socket_read(socket, -1, -1)[1].decode()[:-2]

    if triggerstatus != "1":
        tp_log("Trigger failed: " + str(triggerstatus))
        return 0

    wait(1)  # extra safety margin, can likely be removed

    client_socket_write(socket, (cel_data + "\r\n").encode())
    getvaluestatus, rec, _empty = str(client_socket_read(socket, -1, -1)[1].decode()).split("\r\n")

    if getvaluestatus == "1":
        rec = str(rec).split(",")
    else:
        tp_log("GetValue failed: " + str(getvaluestatus))

    client_socket_close(socket)

    return rec

Input	Type	Description
cel_data	string	The `GVxyyy` get-value command. `x` is the column letter, `yyy` is the row number of the cell to read — e.g. `GVC013` reads cell C13.

This returns a list of the comma-separated values in that cell. It’s commonly used to get an object’s X/Y position, rotation, and an ID number from the camera in one call. An empty result (['']) means the camera found no valid detection.

7. Use the result, and handle no-detection

X_Y_R = get_data_from_cognex('GVC019')
if X_Y_R == ['']:
    tp_popup('No mold detected, please place mold in the detectable square', pm_type=DR_PM_MESSAGE, button_type=1)
    return 0

pos_x = float(X_Y_R[0])
pos_y = float(X_Y_R[1])
pos_r = float(X_Y_R[2])
mold_number = int(X_Y_R[3])

See How to show pop-up messages on the Doosan teach pendant with tp_popup for more on tp_popup().

Troubleshooting

No response after connecting: confirm the robot and camera are on the same IP subnet, and that ip/port match the camera’s actual settings.
Trigger fails: the camera must be in Online Mode — it won’t respond to the SE8 trigger command otherwise.
GetValue failed: check that the job on the camera actually writes a value to the cell you’re reading, and that the cell reference (e.g. GVC019) is correct.