Programmable Logic Controller (PLC), as an industrial computer, integrates data collection, processing, and display. As a data terminal, data display is completely necessary. Although the PLC itself has many indicator lights that can observe the operating status of the CPU unit, input/output unit, and network communication unit of the PLC, it cannot display internal data of the PLC. Computers can achieve internal data display of PLC through communication with PLC and touch screen, but it is expensive and even more wasteful for some small systems that do not require frequent modifications. This article uses dial switches and digital tubes to display PLC internal data, which is easy to operate and cost-effective, and has reference value for experimental teaching and engineering personnel.
(1) Application industries: machining, process control, etc.
(2) Products used: CJ1M (CPU22), CS1W-ID211, CS1W-OD261
(3) Main process points and main problems to be solved: Dynamic display of internal data
(4) Application solution introduction: Using high-frequency transistor output unit, combined with high-speed timer instruction TIMH to achieve dynamic display of internal data.
Dynamic Data Display 2.1 Hardware System Design: The LED digital tube has 7 segments of display lights, which can be used to display 10 digits between 0 and 9. The internal channel data of CJ1M series PLC is generally four digits. If we use each output point to control a display light, then a digital tube requires 7 output points, which obviously requires a large number of output points and is not economical. Here, a digital tube with a built-in decoding circuit, such as CD4511, is selected to automatically translate 8421 code into a 7-segment code. Code 8421 or BCD can display one data bit by adding gating signals to four interfaces. Connect four 8421 input lines to the lowest four bits of an output channel, and connect the input signal of each gate signal to the remaining four bits of the channel. This way, one output channel can display the internal data of the PLC’s four bits (one word).
Related recommendations:
MVI56-LTQ
MVI56-MCM
MVI56-MCMR
MVI56 MNET
MVI56 MNETC
MVI56-PDPMV1
MVI56-PDPS
MVI69-AFC
MVI69E-MBS
MVI69-MCM
MVI69 MNET
MVI69-PDPMV1
MVI69-PDPS
There are no reviews yet.