With the increasing maturity of modern industrial automation, engineers tend to simulate the actual operating cycle of motors and automatically test parameters such as temperature and power through instrument settings. This article presents the simulation test and result analysis of motor operating conditions based on actual arrangements.
The motor industry requires testing the temperature changes of motors during operation, ensuring that the temperature does not exceed certain limits. It also needs to test motor voltage, current, power, and other parameters, displaying all parameters simultaneously for easy viewing and control. While comprehensive motor characteristic testing systems can meet these requirements, they are too expensive, and many testing scenarios do not require such complexity in terms of accuracy.
If the evaluation only considers electrical parameters and temperature performance, the DM100 data acquisition and recorder, in conjunction with the PA310 power meter, can meet the testing requirements. This allows for automatic control of motor testing and simultaneous display of all information in the host computer software. The automatic control aspect will be discussed in detail below.
1.1 Description of Simulated Operating Condition Tests
In reality, motors typically operate in a fixed-sequence cycle of running and stopping. How is this achieved? The usual practice is for engineers to manually control the switching on and off, which is both unreliable in terms of timing and time-consuming. However, the motor's operating cycle can be accurately recorded using the digital output module of a data acquisition and recording device, saving both time and effort.
1.2 Simulation of actual motor operating conditions
1. Hardware and connection requirements
The DM90YD digital output module can be used as a relay output (C contact) when an alarm occurs, or it can be manually operated via the touch screen (ON/OFF).
DO output control: Select the excitation mode, connect COM and NC to the input terminal of the external relay and the external AC power respectively, and connect the output terminal of the external relay to the power supply and the motor.
The motor test current is relatively large, so a relay needs to be converted into a data acquisition DO module that can carry the current. It is an AC control type with an input control voltage of 80~280VAC, a control current of less than 30mA, a load voltage of 24~480VAC, and a maximum load current of 20A.
2. Processing Channel Settings
Select ON for operation channel A001, and set the operation expression to: (Val(A1)+1)%2400;
The operation channel A002 is set to ON, and the operation expression is set to: Val(A1)>=600?-1:1; lower limit of range -2.00, upper limit of range 2.00.
3. Expression settings
(Val(A1)+1)%2400, Val(A1)>=600?-1:1 are the calculation formulas for implementing this working mode, which can be set according to different needs.
For example, if you need to set the run time to 5 minutes and the stop time to 2 minutes, you only need to change the formula to (Val(A1)+1)%4200, Val(A1)>=1200?-1:1. Since the update time is 100ms, 4200 in the formula is the run and stop time, and 1200 is the stop time.
4. Alarm settings for the computing channel
To enable relay switching, the alarm channel is set as shown in Figure 6. The alarm channel is selected as A002, the alarm level is set to ON, the type is set to upper limit, the output type is set to relay, and the output number is set to X0102.
5. Perform calculations and view the data.
After setting up, click "Calculation," select "Start Calculation," and observe the changes in DO in the overview or trend chart to achieve automatic control.
1.3 Test of data acquisition recorder and power meter
Using this connection method, the power meter and data acquisition system are connected to achieve mixed measurement and display, and the data acquisition system's DO (Distribution and Control) is used to automatically control the motor's operation and stop.
Application Case: A motor user wants to achieve a continuous operating mode where the motor runs for three minutes and stops for one minute, as well as simultaneous display of voltage, current, and temperature; this testing requirement is achieved by using DM100 and PA310 via Modbus communication.
1.4 Summary
The combination of a data acquisition recorder and a power meter can solve the conventional technical requirements of motor operating condition simulation testing. The connection is simple and the setup is very quick.
