Configure the Keyence KV Connector
Configure Keyence KV PLC connections, discover instances, create items, select memory and data types, and resolve communication errors.
The Keyence KV Connector communicates with Keyence KV-series PLCs over Ethernet using the Keyence Host Link protocol. Use it to read and write individual PLC memory values, including bits, integers, floating-point values, hexadecimal values, and ASCII text.
This guide explains how to discover or create a Keyence KV instance, configure items manually, select the correct memory and data types, verify communication, and resolve common errors.
Writing to PLC memory can change machine behavior. Confirm the target memory address and data type, then perform test writes only when the connected process is in a safe state.
Before you begin
Make sure that:
- The Keyence KV Connector is installed and enabled.
- Host Link communication over Ethernet is enabled in the PLC.
- You know the PLC IPv4 address and TCP Host Link port. The default Connector port is
8501. - SIA Connect and the PLC can communicate through the configured network interface.
- You know the Keyence memory addresses and data types that the application must use.
- Another application is not preventing the PLC from accepting the required Host Link connection.
Memory areas and valid address ranges differ between Keyence PLC models. Check the programming manual for the connected PLC before creating items.
Discover a Keyence KV instance
The Connector can discover compatible Keyence KV PLCs on a local IPv4 network. It does not support item discovery.
- In the Edge Portal, open Configuration > Connectors.
- Find the installed Keyence KV Connector.
- Start instance discovery.
- Configure the discovery parameters if the PLC does not use the default interface or port range.
- Start the search and wait for it to finish.
- Select the required PLC from the results.
- Import the instance.
- Open the imported instance and verify its address, port, and timeout.
A discovered instance is created with the detected IPv4 address and port. Its communication timeout is set to 2000 ms.
Discovery parameters
| Parameter | Default | Accepted values | Description |
|---|---|---|---|
| Scan duration (ms) | 60000 |
1000 to 300000
|
The total discovery window in milliseconds. |
| Network interface | eth0 |
An available interface or All IPv4 interfaces | The interface used for the UDP broadcast and TCP subnet scan. |
| UDP ports | 8500-8510 |
Comma-separated ports and ranges | The ports used for the Host Link discovery broadcast. For example, 8501 or 8500-8510. |
| TCP ports | 8500-8510 |
Comma-separated ports and ranges, up to 64 ports | The ports checked when identifying a PLC through TCP Host Link. |
Discovery first broadcasts a Keyence unit-type request. It then checks the selected TCP ports and may probe up to 256 IPv4 hosts on the selected subnet. Use a specific network interface and a narrow port range to reduce the search time.
An active KV STUDIO connection can prevent identification from succeeding. Disconnect KV STUDIO temporarily if a reachable PLC does not appear in the results.
Create an instance manually
- In the Edge Portal, open Workspace > Instances.
- Select Add instance.
- Select the Keyence KV Connector.
- Enter a descriptive instance name.
- Enter the PLC IPv4 address.
- Configure the port and timeout.
- Save the instance.
Instance parameters
| Parameter | Required | Default | Description |
|---|---|---|---|
| Address | Yes | None | The numeric IPv4 address of the PLC. Hostnames are not accepted. |
| Port | Yes | 8501 |
The TCP port configured for Host Link communication. |
| Timeout | Yes | 2000 |
The connection, read, and write timeout in milliseconds. |
The Connector keeps a separate connection for each configured PLC and attempts to reconnect automatically when a connection is lost.
Create an item
Keyence KV does not provide item browsing through this Connector. Create each item manually from the PLC memory information.
- Open the Keyence KV instance.
- Open the Items tab.
- Select Add item.
- Enter a descriptive item name.
- Enter the PLC address in Memory address.
- Select Bit device or Word device in Memory type.
- For a word device, select the required Data type.
- For ASCII data, enter the required number of PLC words in String lenght.
- Configure whether the item can be read, written, or both.
- Save the item.
Item parameters
| Parameter | Required | Description |
|---|---|---|
| Memory address | Yes | The Keyence device symbol followed by its memory location. Examples include D201, DM0, and R0. Use the exact device notation supported by the PLC model. |
| Memory type | Yes | Select Bit device for a direct bit-memory address. Select Word device for word memory and for a bit inside a word. |
| String lenght | For ASCII | The number of PLC words to read or write for an ASCII value. Each word can contain up to two characters. The field name is displayed with this spelling in the current Connector. |
| Data type | For word devices | Controls the number of PLC words used and how the value is converted. |
Address format: Enter a single memory address. The range suffix used in older documentation, such as D201-4, is not supported by the current Connector.
Choose the memory type
| Memory type | Use | Example | Behavior |
|---|---|---|---|
| Bit device | A direct Keyence bit-memory device | R0 |
The Connector reads a bit value and normalizes written values to 0 or 1. |
| Word device | A numeric, hexadecimal, floating-point, or ASCII value | D201 |
The selected data type determines the size and conversion. |
| Word device with BIT data type | One bit inside a word | D10.3 |
The bit number after the dot must be from 0 to 15. |
Writing a BIT inside a word uses a read-modify-write operation. Avoid using this method when the PLC program or another client can change other bits in the same word at the same time.
Choose the data type
| Data type | Size | Accepted write value |
|---|---|---|
| BIT | 1 bit inside a word |
0 or 1
|
| Short | 1 word | Signed 16-bit integer from -32768 to 32767
|
| Long | 2 words | Signed 32-bit integer from -2147483648 to 2147483647
|
| Word | 1 word | Unsigned 16-bit integer from 0 to 65535
|
| DWord | 2 words | Unsigned 32-bit integer from 0 to 4294967295
|
| Hexadecimal 16Bit | 1 word | Hexadecimal value from 0 to FFFF, without a 0x prefix |
| Hexadecimal 32Bit | 2 words | Hexadecimal value from 0 to FFFFFFFF, without a 0x prefix |
| Float | 2 words | A 32-bit IEEE 754 decimal value |
| Double | 4 words | A 64-bit IEEE 754 decimal value |
| ASCII | Configured by String lenght | Text that fits within the configured capacity of two characters per word |
| Unknown Data Type | Not applicable | Do not select this value. It cannot create a valid read or write request. |
Float and Double writes must use ordinary decimal notation. Exponent notation is not accepted by the current value validator.
Verify the connection
- Create a readable item for a known PLC memory address.
- Enable the instance and item.
- Confirm that the item receives the expected value without an instance or item error.
- Compare the value with KV STUDIO or another trusted PLC view.
- If writing is required, write a controlled test value while the process is safe.
- Confirm the value in the PLC, then restore the original value.
An error on one item does not stop the Connector from processing the remaining items.
Troubleshoot the Keyence KV Connector
| Error or symptom | Likely cause | Action |
|---|---|---|
invalid address on the instance |
The instance Address is not a numeric IPv4 address. | Enter the PLC address in IPv4 format, such as 10.20.30.50. Do not include a protocol prefix or port. |
invalid port |
The Port does not contain a numeric value. | Enter the TCP Host Link port configured in the PLC. The Connector default is 8501. |
Not connected to PLC |
The Connector could not establish or restore the TCP connection. | Check the PLC power, cable, IP address, subnet, routing, firewall, Host Link settings, and port. Confirm that another client is not occupying the connection. |
Timeout reading (<value>ms) |
The connection was established, but the PLC did not reply within the configured timeout. | Confirm the port and Host Link configuration. Check network quality and whether another application is communicating with the PLC. Increase the timeout only when required. |
invalid address on an item |
The PLC rejected the command or memory address. | Check the device symbol, location, selected memory type, and whether the address exists on the PLC model. |
Data item parameters invalid |
The Connector could not create a complete Host Link command. | Check the memory address, data type, ASCII length, and write value. |
data type not boolean |
A dotted bit address is not configured as a valid BIT item, or the write value is not 0 or 1. |
Select Word device and BIT, then use a bit number from 0 through 15. |
bit number invalid |
The number after the dot is missing or outside the supported range. | Use a dotted address such as D10.3 with a bit number from 0 through 15. |
value out of range |
The write value is outside the range of the selected type. | Use a value within the range shown in the data type table. |
invalid format for data type |
The write value does not match the selected data type. | Remove unsupported prefixes, separators, or exponent notation. Use 0 or 1 for BIT. |
data lenght invalid |
The request requires an invalid number of words, or an ASCII value exceeds the configured capacity. | For ASCII, increase String lenght so the value fits at up to two characters per PLC word. |
| A read or write socket error | The connection closed, no data was received, or the operating system reported a network error. | Check the network path and PLC connection state. Review the full item error and system logs for the affected command. |
| Discovery finds no PLCs | The wrong interface or ports are selected, UDP broadcast is blocked, the PLC is outside the scanned subnet, or KV STUDIO is using the connection. | Select the PLC-facing interface, enter the configured port, permit local UDP and TCP traffic, and disconnect KV STUDIO temporarily. Create the instance manually if discovery cannot cross the network boundary. |
If the values are incorrect without an error, check the selected data type and starting address. Multiword types consume consecutive PLC words. Confirm the word order and stored representation in the PLC program.