Read performance MindConnect Elements¶
All MindConnect Elements have a clear limitation on soft limits(unmonitored number of data points and data connections). The only fixed limit is 1050 data points. Within the soft limits, you can configure data connections and data points without reaching the limits. For 250 datapoints read per second, the upload bandwidth should be at least 0.5 MB/s.
The following describes how to proceed if you want to exceed these limits.
Tested MindConnect limits¶
|Max mount of data points can be configured (Fix)||1050|
|Data points OPC UA / S7 / Modbus TCP||250|
|(read per second)|
|Connections to data providers||30|
|String data points||10|
|Data points - Modbus RTU RS485 / RS422 - 9,6 kBd||20|
|Data points - Modbus RTU RS485 / RS422 - 19,2 kBd||35|
|Data points - Modbus RTU RS485 / RS422 - >= 38,4 kBd||80|
|Data points - Modbus RTU RS232 - 57,6 kBd||40|
Adaptions of the limits¶
Subsequently listed are the parameters the influence the read performance of a MindConnect Element. By varying one of these parameters all others will be affected as well. These are the variables:
- Performance of MindConnect hardware
- Number of connections to data providers
- Type of connection to providers (S7 / OPC UA / Modbus / ...)
- Amount of data points per second
- Type of data points (String or no string)
- Performance of data provider (PLC, OPC Server)
- Reading data from a data provider will always cause an effect on it. The performance of the data provider (PLC / OPC Server / Modbus) is one of the most important limiting factors. If more devices (e.g. OPC server, HMIs, SCADA systems,...) are connected to this data provider (e.g. PLC) the reading cycle can rise.
- For MindConnect Software Agent, the readings are not applicable as it depends on the hardware for a particular agent and configuration.
Example calculations (MindConnect Nano)¶
- It can be possible to read 300 data points per second out of a PLC. This is possible if the PLC is powerful and just one data provider is used.
- It can be possible to read 1000 data points out of 30 data providers if the reading cycle will be switched to 4sec.
- It can be possible to read out of 35 data providers if you just read 200 data points per second.
To make sure a configuration works for your setup it needs to be monitored over a longer period of time.
System Test results¶
The following tables show how long it takes to read a data item from one of the devices. These are not fixed values but an indication of how the devices would react.
|Type||MS per data point read: Min||MS per data point read: Mid||MS per data point read: Max|
|S7 ET200S CPU||0,89||2,09||3,71|
|OPC UA @ PC¹⁾||2,38||6,64||8,53|
|OPC UA@ PLC||2,66||3,27||4,69|
¹⁾ OPC UA @ PC always depends on the hardware.
- Read of a string data point you have to multiply the time with 2,5 per data point
- All devices are around 75% full