Collecting struct variables with EtherNet/IP Collector

SpeeDBee Synapse:v4.9.9Last updated:2026-08-20

Purpose

Collect variables defined as structs using the EtherNet/IP Collector.

Project files

This is the project file used in this example.

• EtherNetIPCollectorStructVars.sspj

Note: Import requires SpeeDBee Synapse version 4.9.9 or later.
Note: Update the EtherNet/IP Collector connection settings to match your environment.
Note: The variables used on the PLC side must be defined in advance.

What you will learn

• How to configure collection of struct variables
• How to configure collection of struct arrays
• How to configure collection of nested struct variables
• How to configure collection when the number of array elements exceeds the limit (200)

Requirements

Collect the following struct variables using the EtherNet/IP Collector. The targets include single structs, struct arrays, nested structs, and structs that exceed the array limit.

motor_status (Single Struct: MotorStatus)

A single struct variable. Collects multiple primitive-type members such as BOOL, DINT, REAL, and STRING as a single tag.

channel_data_list (Struct Array: ARRAY[0..15] OF ChannelData)

A struct array variable. Collects an array tag of type ChannelData with 16 elements (0..15).

device_packet (Nested Struct: DevicePacket)

A nested struct variable. Collects data from the parent struct DevicePacket, which contains child structs DeviceMeta and ProcessValue.

batch_values (Struct Exceeding Array Limit: BatchValues)

A struct variable with an array member that exceeds the array limit (200). Collects the struct including values (ARRAY[0..249] OF USINT).

Components used

• EtherNet/IP Collector (data collection)

Workflow

1. Collect the following data with the EtherNet/IP Collector:
   • motor_status (MotorStatus)
   • channel_data_list (ARRAY[0..15] OF ChannelData)
   • device_packet (DevicePacket)
   • batch_values (BatchValues)

Setup

1. Enter the connection settings for the EtherNet/IP Collector.

   

2. Configure the variables to collect. Start by adding the motor_status variable. For structs, check the Struct checkbox to enable adding each member via ADD COLUMN.

   

   Column names for struct members

   You can assign column names to each member of a struct, but they do not need to match the member names defined on the PLC side. Data collection works as long as the member data types, array counts, and definition order match.

3. Add the channel_data_list variable. The current EtherNet/IP Collector does not support bulk retrieval of struct arrays. Therefore, specify channel_data_list[0] to retrieve only the first element.

   

   Retrieving individual array elements

   Due to EtherNet/IP Collector specifications, bulk retrieval of struct arrays is not supported. You must specify an individual array element by index in the variable name (e.g., channel_data_list[0]).
   To retrieve all elements, you must specify each element individually — such as channel_data_list[0], channel_data_list[1], channel_data_list[2], etc. — and configure members for each one.

4. Add the device_packet variable. The current EtherNet/IP Collector does not support bulk retrieval of nested structs. Specify the child structs individually using device_packet.Meta and device_packet.Pv to retrieve only the Meta and Pv data.

   

   Retrieving individual struct members

   Due to EtherNet/IP Collector specifications, bulk retrieval of nested structs is not supported. Specify each child struct member individually using dot notation in the variable name (e.g., device_packet.Meta, device_packet.Pv).

5. Add the batch_values variable. Due to EtherNet/IP Collector specifications, the maximum number of array elements configurable per column (member) is 200. Split the retrieval into 200 and 50.

   

   Splitting retrieval of struct array members

   The EtherNet/IP Collector has a maximum of 200 array elements per column (member). If the array count exceeds 200, you must split it across multiple columns. Note: this approach applies only to array members inside a struct. If the variable itself is an array, splitting in the same way is not possible.

6. Save the settings and start the EtherNet/IP Collector.

   

Checking the output

The following is a sample of data collected by the EtherNet/IP Collector and output as JSON via the JSON Serializer.

Output file (JSON)

The sections below compare the initial values set on the PLC side with the JSON output to confirm that values are being retrieved correctly.

Verification: motor_status

JSON output excerpt

"CollectEipData:ms_run_signal": true,
"CollectEipData:ms_alarm_signal": false,
"CollectEipData:ms_speed_rpm": 1450,
"CollectEipData:ms_temperature_c": 43.200,
"CollectEipData:ms_recipe_name": "RCP_TEST01",

Values confirmed in the tool

Verification: channel_data_list[0]

JSON output excerpt

"CollectEipData:cd0_channel_id": 1,
"CollectEipData:cd0_enable": true,
"CollectEipData:cd0_value": 10.200,
"CollectEipData:cd0_quality": 100,
"CollectEipData:cd0_timestamp_ms": 1722301200,

Values confirmed in the tool

Verification: device_packet.Meta / device_packet.Pv

JSON output excerpt

"CollectEipData:dp_device_id": 9001001,
"CollectEipData:dp_line_no": 3,
"CollectEipData:dp_station_no": 12,
"CollectEipData:dp_device_name": "PACKER_TEST01",
"CollectEipData:dp_pressure_kpa": 245.800,
"CollectEipData:dp_flow_lpm": 36.400,
"CollectEipData:dp_temperature_c": 41.700,
"CollectEipData:dp_vibration_mms": 2.300,

Values confirmed in the tool

Verification: batch_values

Due to the array limit constraint, values is split into two columns (bv_values1 and bv_values2) in the output.

JSON output excerpt

"CollectEipData:bv_values1": [0 , 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 , 76 , 77 , 78 , 79 , 80 , 81 , 82 , 83 , 84 , 85 , 86 , 87 , 88 , 89 , 90 , 91 , 92 , 93 , 94 , 95 , 96 , 97 , 98 , 99 , 100 , 101 , 102 , 103 , 104 , 105 , 106 , 107 , 108 , 109 , 110 , 111 , 112 , 113 , 114 , 115 , 116 , 117 , 118 , 119 , 120 , 121 , 122 , 123 , 124 , 125 , 126 , 127 , 128 , 129 , 130 , 131 , 132 , 133 , 134 , 135 , 136 , 137 , 138 , 139 , 140 , 141 , 142 , 143 , 144 , 145 , 146 , 147 , 148 , 149 , 150 , 151 , 152 , 153 , 154 , 155 , 156 , 157 , 158 , 159 , 160 , 161 , 162 , 163 , 164 , 165 , 166 , 167 , 168 , 169 , 170 , 171 , 172 , 173 , 174 , 175 , 176 , 177 , 178 , 179 , 180 , 181 , 182 , 183 , 184 , 185 , 186 , 187 , 188 , 189 , 190 , 191 , 192 , 193 , 194 , 195 , 196 , 197 , 198 , 199]
"CollectEipData:bv_values2": [200 , 201 , 202 , 203 , 204 , 205 , 206 , 207 , 208 , 209 , 210 , 211 , 212 , 213 , 214 , 215 , 216 , 217 , 218 , 219 , 220 , 221 , 222 , 223 , 224 , 225 , 226 , 227 , 228 , 229 , 230 , 231 , 232 , 233 , 234 , 235 , 236 , 237 , 238 , 239 , 240 , 241 , 242 , 243 , 244 , 245 , 246 , 247 , 248 , 249]
"CollectEipData:bv_valid_count": 250,
"CollectEipData:bv_batch_id": 1,
"CollectEipData:bv_collect_at_ms": 1722301230

Values confirmed in the tool