Usage guide

Available nodes

Node	Purpose
kvhostlink-connection	Shared KEYENCE KV Host Link TCP/UDP connection config.
kvhostlink-read	Reads one or more high-level addresses into msg.payload.
kvhostlink-write	Writes one or more high-level address/value updates.

kvhostlink-connection config node

Field	Required	Default	Description
Name	No	Empty	Display name.
Host	Yes	Empty	PLC host name or IP address.
Port	Yes	8501	TCP or UDP port.
Transport	Yes	tcp	tcp or udp.
Timeout ms	Yes	3000	Response timeout in milliseconds.
PLC Profile	Yes	keyence:kv-x500	Canonical lowercase profile value.

Accepted profile values are listed in PLC profiles.

kvhostlink-read node

Config field	Description
Name	Display name.
Connection	kvhostlink-connection config node.
Source	Literal text, msg, flow, global, or env.
Addresses	Literal address list when Source is str.
Output	object, array, or single value when one address is requested.
Metadata	full, minimal, or off.
Errors	throw, msg.error, or second output.

Input msg field	Description
msg.addresses	String or array of addresses. Takes priority over the configured source.
msg.payload	String or array of addresses when msg.addresses is not set.
msg.topic	connect, disconnect, or reinitialize for connection control.
msg.connect	Set to true to connect.
msg.disconnect	Set to true to disconnect.
msg.reinitialize	Set to true to close and reconnect.

Output msg field	Description
msg.payload	Read result as an object, array, or scalar value.
msg.kvhostlink	Metadata when enabled.
msg.error	Error object when Errors is msg.error.

kvhostlink-write node

Config field	Description
Name	Display name.
Connection	kvhostlink-connection config node.
Source	Literal text, msg, flow, global, or env.
Static updates	JSON object or address=value lines when Source is str.
Metadata	full, minimal, or off.
Errors	throw, msg.error, or second output.

Input msg field	Description
msg.updates	Object or string updates. Takes priority over msg.payload.
msg.payload	Object or string updates when msg.updates is not set.
msg.address	Single address for one write.
msg.dtype	Optional data type inserted into msg.address when the address has no type suffix.
msg.value	Single write value. If omitted, msg.payload is used.
msg.topic	connect, disconnect, or reinitialize for connection control.
msg.connect	Set to true to connect.
msg.disconnect	Set to true to disconnect.
msg.reinitialize	Set to true to close and reconnect.

Output msg field	Description
msg.payload	Original payload is passed through.
msg.kvhostlink	Metadata when enabled.
msg.error	Error object when Errors is msg.error.

The second output receives a copy of the message with error when Errors is Second output.

Address syntax

Form	Example	Meaning
Word value	DM100	Read or write the default unsigned word value.
Signed 16-bit	DM100:S	Interpret one word as signed 16-bit.
Unsigned 32-bit	DM120:D	Interpret two words as unsigned 32-bit.
Signed 32-bit	DM130:L	Interpret two words as signed 32-bit.
Float32	DM130:F	Interpret two words as a 32-bit float.
Hex word	DM140:H	Read or write a word as uppercase hexadecimal text.
Comment read	DM145:COMMENT	Read the device comment string.
Bit in word	DM150.3	Read or write bit 3 in DM150.
Word array	DM160,4	Read or write four consecutive default values.
Bit array	R200,4	Read or write four consecutive relay bits.
Timer preset	T10	Read timer preset value.
Counter preset	C10	Read counter preset value.

Use : for data types and .0 through .F for bit-in-word access. DM100.D means bit D inside DM100; use DM100:D for a 32-bit value.

Timer and counter

T10 and C10 use the high-level timer/counter behavior. Reads return the preset value for compatibility with ordinary scalar reads. Timer/counter preset writes use Host Link WS and WSS, which are supported only on KV-8000/7000-series CPU units. Other CPU units may return PLC error E1.

Use TC, TS, CC, and CS when you want the timer/counter current/contact device families directly.

Connection control messages

Both read and write nodes accept connection control messages.

Message	Action
msg.topic = "connect"	Connect the shared connection.
msg.topic = "disconnect"	Disconnect the shared connection.
msg.topic = "reinitialize"	Disconnect, then connect again.
msg.connect = true	Connect the shared connection.
msg.disconnect = true	Disconnect the shared connection.
msg.reinitialize = true	Disconnect, then connect again.

Metadata output

Metadata mode	msg.kvhostlink fields
full	Read nodes add addresses and connection; write nodes add updates and connection.
minimal	Adds itemCount and metadataMode.
off	Leaves msg.kvhostlink unchanged.

The connection metadata contains host, port, transport, and timeout.

Error handling

Errors setting	Behavior
Throw	Calls Node-RED done(error).
msg.error	Adds the error object to msg.error and sends the message on output 1.
Second output	Sends normal messages on output 1 and error messages on output 2.