Delta DVP/AS Modbus Master

Purpose

This plugin reads and writes DVP and AS300 devices using Delta PLC address rules. It is named DeltaMaster in the device selector.

See Collection Configuration for common channel, device, variable, data-format, and batch settings. This page covers only Delta series selection, address differences, and debug.

Open the plugin

Open Development Configuration → Collection Configuration, create a TCP client, TCP server, or serial channel matching the field link, then create a device using DeltaMaster.

Supported scope

Item	Description
Channels	TCP client, TCP server, and serial.
PLC series	DVP and AS300.
Data types	Boolean, Byte, common signed/unsigned integers, Float, Double, and String.

Plugin properties

Setting	Default	Description
PLC series	DVP	Select DVP or AS300; the series controls logical address mapping.
Modbus framing	ModbusTcp	Select TCP, RTU, or ASCII framing to match the field link.
Default station	1	Used when the variable address has no s= option.

Multi-byte values use CDAB by default. Check the common data-format settings when a numeric value is incorrect.

Address rules

Series	Bit addresses	WORD addresses
DVP	S0, X0, Y0, T0, C0, M0, D0.0	D0, T0, C0
AS300	SM0, HC0, S0, X0.0, Y0.0, T0, C0, M0, D0.0	SR0, HC0, D0, X0, Y0, C0, T0, E0

• Enter DVP X and Y offsets in octal.
• s=2;D0 overrides the device default and uses station 2.
• The X input area is read-only.

Special methods

This plugin has no additional special methods. Variables use the address rules above directly.

Functions

Function	Purpose
Read and write	Read a confirmed point and write only to an approved test point.
Messages	View sent and received frames, protocol fields, and error details.

Device debug

Open Development Configuration → Collection Configuration, select the Delta device, and click More Functions, then open Debug.

Feature	Purpose
Read/Write	Reads one Delta address or performs an approved write.
Messages	Shows protocol requests, responses, and connection logs.

Read/Write

Enter a Delta address, data type, and array length. Read a known point first and write only after site approval.

Messages

Start message capture to inspect the station, address mapping, requests, responses, and Modbus exception codes.

Verify the configuration

1. Read one known address and verify the PLC series, station, value, and data type.
2. Confirm a valid request and response under Messages.
3. Write only an approved test point and read it back as required by the site.

Troubleshooting

Symptom	Check
Address read fails	PLC series, area, DVP octal X/Y offset, and station.
Modbus exception is returned	Framing, function code, address range, and quantity.
Value is incorrect	Data type, array length, and default CDAB byte order.
Write fails	Read-only X area, variable permission, function code, and PLC write protection.

Related links

• Collection Configuration: Common channels, devices, variables, and data format.
• Plugin Manual Index: Other collection and data-forwarding plugins.