PLC integration

Compatible with: picoScan100

Use the CoLa command protocol over a TCP/IP socket to receive measurement, field-evaluation, and I/O data from picoScan100 on Siemens, Beckhoff, Mitsubishi, or Rockwell PLCs. SICK does not provide maintained picoScan100 PLC function blocks; implement a small length-prefixed receive routine using the controller's native TCP socket API.

Interface and approach

For PLC applications, use CoLa B on TCP port 2112. Its length-prefixed telegrams are easier to process than CoLa A on port 2111. Open one bidirectional TCP connection from the PLC to the sensor, keep it open, and poll the required values by sending an sRN request and reading the matching sRA response on that same connection.

Interface	Transport	Suitable use
CoLa A / B	TCP 2111 / 2112	PLC commands and telegram access
Compact / MSGPACK	UDP or TCP	High-rate scan streams to a PC or edge device
REST API	HTTP(S) 80 / 443	Configuration, diagnostics, and firmware updates

Configure the sensor once through SOPASair: use a fixed IP address reachable from the PLC, configure scan profiles, field-evaluation groups, and I/O, then export a parameter backup. Do not repeatedly configure the sensor from cyclic PLC logic. Enable LMDscandata only when the PLC requires distance data.

Polling and CoLa B framing

The PLC is the client and connects to <device-ip>:2112. Send a request, receive one complete telegram, parse it, and reconnect after an error or timeout.

connect(device_ip, 2112)
loop:
  send(frame("sRN LMDscandata"))
  reply = receive_one_telegram()
  parse(reply)

Every CoLa B telegram has this layout:

Field	Size	Value
Start	4 bytes	02 02 02 02
Length	4 bytes	Big-endian payload length
Payload	N bytes	Command type, name, and data
Checksum	1 byte	XOR of all payload bytes

TCP is a byte stream: a receive operation can return a partial telegram or several telegrams. Buffer incoming bytes; after at least eight bytes are available, validate the start sequence, read the big-endian length, then wait for exactly 8 + length + 1 bytes. Validate the XOR checksum, consume one telegram, and retain any remaining bytes for the next call.

Common telegrams

Telegram	Purpose	PLC consideration
SCdevicestate	Device health	Poll slowly and invalidate dependent values when not ready.
LMDscandata	Distance and optional RSSI data	Reduce it below the network MTU where possible.
perpendicularDistanceResult	Minimum and maximum distance to a field boundary	Its value can remain unchanged after the field is clear; gate it with field state.
FieldEvaluationResult	Free/occupied result for each evaluation group	Map each group index to the configured physical zone.
LIDinputstate / LIDoutputstate	Digital I/O states	Use to mirror sensor I/O in the PLC process image.

Request each with sRN <name> and parse the sRA <name> ... response. Confirm the exact payload layout, byte offsets, and data types against the Telegram Listing in the operating instructions for the installed firmware.

To keep LMDscandata manageable, use only the required echo, disable RSSI when not needed, restrict the scan angle, and select the coarsest acceptable angular resolution. A small telegram reduces PLC processing load and TCP segmentation.

Controller notes

Controller	TCP mechanism
Siemens S7-1500 / S7-1200	Open User Communication: TCON_IP_v4, TSEND_C, and TRCV_C; use variable-length receives.
Siemens S7-300 / S7-400	CP module with AG_SEND / AG_RECV and FB54 TCP.
Beckhoff TwinCAT 3	Tc2_TcpIp: FB_SocketConnect, FB_SocketSend, and FB_SocketReceive.
Mitsubishi GX Works2 / iQ	Ethernet socket services: SP_SOCOPEN, SP_SOCSND, SP_SOCRCV, and SP_SOCCLOSE.
Rockwell / Allen-Bradley	Raw TCP socket object with MSG instructions for connect, write, read, and close.

The transport API differs, but the CoLa B framing and receive-buffer logic are identical for every PLC.

Troubleshooting

Symptom	Cause	Action
Connection refused on 2112	Incorrect network settings or CoLa B disabled	Verify the sensor IP/subnet and CoLa B configuration.
No response	Malformed request or wrong telegram name	Validate start bytes, length, XOR checksum, and case-sensitive command name.
sFA error response	Unsupported or unavailable variable	Check the Telegram Listing and firmware version.
Receive never completes	Fixed-size receive or TCP fragmentation	Buffer data and use the length field to determine the complete frame.
Misaligned data	Concatenated frames or unconsumed bytes	Consume exactly one frame and retain the buffer remainder.
Frozen values	Repeated scan or stale perpendicular-distance result	Verify scan counter/timestamp and use FieldEvaluationResult to validate the distance.