The TD400C is a dedicated text display for S7-200, used to view, monitor, and modify process variables in S7-200 user programs. Its appearance is shown in Figure 21-1.
The TD400C is an upgrade from the TD200C, capable of displaying four lines of text, with a maximum of 12 Chinese characters per line, at a resolution of 192×64 pixels. The TD400C supports two display fonts and both Chinese and English text.
The TD400C has 8 function keys, which, when used in conjunction with the Shift key, can be used to define up to 16 function keys.
Connection between 2TD equipment and S7-200
(1) One-to-one configuration
A one-to-one configuration uses a TD/CPU cable to connect the communication port of one TD device and one CPU. The default address of the TD device is 1, and the default address of the CPU is 2.
(2) The TD device is connected to the CPU communication port in the network.
When multiple S7-200 CPUs are networked, one of the CPUs uses a network connector with a programming port for its communication port, and the cable from the TD device is connected to this programming port. In this case, the TD device's DC24V power supply is provided by the CPU.
(3) TD equipment access to the communication network
The TD device can be connected to the network using a network connector and a PROFIBUS cable. At this point, only the communication signal lines (3-pin and 8-pin) are connected, not the power lines (2-pin and 7-pin). A DC 24V power supply is required to power the TD device.
Application examples:
Project: Application of connecting S7-200 CPU and TD400C.
Requirements: When the F1 key of the TD400C is pressed, Q0.0 is set to ON and "Indicator status: ON" is displayed on the TD400C screen; when the F2 key of the TD400C is pressed, Q0.0 is reset to OFF and "Indicator status: OFF" is displayed on the TD400 screen.
Step 1: Configuration Text Display Wizard
Open the STEP7-Micro/Win software, click the menu "Tools → Text Display Wizard", as shown in the figure, select the TD model as TD400C, and click the "Next" button.
Configure the settings for the TD keyboard key control as shown in the figure below. Set keys F1 and F2 to "Instantaneous Contact" and click the "Next" button.
Step 2: Writing the PLC program
Notice:
The PLC's default address is 2, and the communication rate is 9.6 kb/s. The TD device's default address is 1, and the communication rate is also 9.6 kb/s. If both the PLC and the TD device use these default settings, communication will be normal. If a connection fails, the address and communication rate need to be checked.
If the TD device indicates that there are no data blocks, the data block address needs to be set. In this example, the address is VB191.
