# Why is Modbus Getter Not Receiving Data from Modbus Server?

**URL:** <https://discourse.nodered.org/t/why-is-modbus-getter-not-receiving-data-from-modbus-server/80875>\
**Category:** Industrial\
**Tags:** function-node\
**Created:** [29 August 2023 02:02 UTC](https://discourse.nodered.org/t/why-is-modbus-getter-not-receiving-data-from-modbus-server/80875 "2023-08-29T02:02:13Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![nicholaswu](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/nicholaswu/32/19540_2.png) [@nicholaswu](https://discourse.nodered.org/u/nicholaswu)\
**Post date:** [29 August 2023 02:02 UTC](https://discourse.nodered.org/t/why-is-modbus-getter-not-receiving-data-from-modbus-server/80875/1 "2023-08-29T02:02:13Z")

</div>

Workflow as follows:

```auto
[
    {
        "id": "8433851b34033b3b",
        "type": "modbus-read",
        "z": "1ba6b61acf69773f",
        "name": "test",
        "topic": "test",
        "showStatusActivities": false,
        "logIOActivities": false,
        "showErrors": false,
        "showWarnings": true,
        "unitid": "0",
        "dataType": "Coil",
        "adr": "1",
        "quantity": "1",
        "rate": "1",
        "rateUnit": "m",
        "delayOnStart": false,
        "startDelayTime": "",
        "server": "b242b402bba0f67f",
        "useIOFile": false,
        "ioFile": "",
        "useIOForPayload": false,
        "emptyMsgOnFail": false,
        "x": 370,
        "y": 60,
        "wires": [
            [
                "17c8a4504ad23109"
            ],
            []
        ]
    },
    {
        "id": "17c8a4504ad23109",
        "type": "debug",
        "z": "1ba6b61acf69773f",
        "name": "debug 6",
        "active": true,
        "tosidebar": true,
        "console": false,
        "tostatus": false,
        "complete": "false",
        "statusVal": "",
        "statusType": "auto",
        "x": 600,
        "y": 60,
        "wires": []
    },
    {
        "id": "f1c9a936ac0bce42",
        "type": "debug",
        "z": "1ba6b61acf69773f",
        "name": "DO格式",
        "active": true,
        "tosidebar": true,
        "console": false,
        "tostatus": false,
        "complete": "true",
        "targetType": "full",
        "statusVal": "",
        "statusType": "auto",
        "x": 580,
        "y": 100,
        "wires": []
    },
    {
        "id": "dc61d5bb20b3e373",
        "type": "modbus-getter",
        "z": "1ba6b61acf69773f",
        "name": "讀取用電量不足/SOC準備量不足/機組剩餘可用量不足",
        "showStatusActivities": true,
        "showErrors": true,
        "showWarnings": true,
        "logIOActivities": false,
        "unitid": "0",
        "dataType": "Coil",
        "adr": "1",
        "quantity": "1",
        "server": "b242b402bba0f67f",
        "useIOFile": false,
        "ioFile": "",
        "useIOForPayload": false,
        "emptyMsgOnFail": false,
        "keepMsgProperties": true,
        "delayOnStart": false,
        "startDelayTime": "",
        "x": 220,
        "y": 160,
        "wires": [
            [
                "f1c9a936ac0bce42",
                "5b83066048133419"
            ],
            []
        ]
    },
    {
        "id": "b242b402bba0f67f",
        "type": "modbus-client",
        "name": "Ｍodbus server",
        "clienttype": "tcp",
        "bufferCommands": true,
        "stateLogEnabled": false,
        "queueLogEnabled": false,
        "failureLogEnabled": true,
        "tcpHost": "127.0.0.1",
        "tcpPort": "502",
        "tcpType": "DEFAULT",
        "serialPort": "/dev/ttyUSB",
        "serialType": "RTU-BUFFERD",
        "serialBaudrate": "9600",
        "serialDatabits": "8",
        "serialStopbits": "1",
        "serialParity": "none",
        "serialConnectionDelay": "100",
        "serialAsciiResponseStartDelimiter": "0x3A",
        "unit_id": "0",
        "commandDelay": "1",
        "clientTimeout": "1000",
        "reconnectOnTimeout": false,
        "reconnectTimeout": "2000",
        "parallelUnitIdsAllowed": true,
        "showWarnings": true,
        "showLogs": true
    }
]

```

I am using a Modbus Client Simulator to connect to the Modbus Server. Initially, I was using Modbus Read to fetch the data, but now I want to replace it with Modbus Getter. However, in my tests, only Modbus Read is detecting changes from the Modbus Server node, while Modbus Getter is not. The output is as follows:

```auto
2023/8/29 9:54:01 node: debug 6
test : msg.payload : array[8]
[true, false, false, false, false, false, false, false]

2023/8/29 9:55:01 node: debug 6
test : msg.payload : array[8]
[false, false, false, false, false, false, false, false]

```

thanks for your help

---

<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/1X/d073cd938eafa2e558d7c2cd59003b3ef4963033.png) [@system](https://discourse.nodered.org/u/system)\
**Post date:** [28 October 2023 02:03 UTC](https://discourse.nodered.org/t/why-is-modbus-getter-not-receiving-data-from-modbus-server/80875/2 "2023-10-28T02:03:05Z")

</div>

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