A introduction to our product HLP2D digital panel meters with the programmable decimal and extensive output

   <Back to homepage>

  Our new product HLP2D digital panel meters is similar to HLP2C in function. Besides the two bits extensive output, it has a programmable decimal, that is to say, the decimal of the digital panel meter can be controlled by program, which greatly enhanced the range that can be displayed by the digital panel meters. HLP2D digital panel meter, equal to HLP2C, have two relay output ports. The extensive ports and the decimal are all programmable with PLC.

1.HLP2D digital panel meters circuit diagram

    The circuit diagram of HLP2D digital panel meters is similar to HLP2C, Only 8、9、10 ports not use.　

2. Data structure

     HLP2C、HLP2D digital panelmeters have two and a half bytes(20 bits), the last 16 of which is the data need to display. The first four bits of HLP2C are extensive output bits; the first two bits of ;HLP2D meter is to ensure the position of the decimal, while the third and fourth bits are extensive output bits. The data struction is well-presented in the following graph.

How to use the extensive bits of HLP2C,D: since the extensive output is data signal from the double-wire serial interface of PLC, it may be influenced by some factors and to lower the transmission speed. We recommend it use in the non-control field, such as indicator lamp; if it must be used in control field, it can be used in the insignificant situation with low speed.

3.  Programming skills of PLC digital panel mters 

  Take OMRON PLC as an example to illustrate the method, other PLC can refer to this method. 
there are five parts in the process of the programming.

1: generate clock pulse. "KEEP" is used to generate pulse according to the period of scanning in OMRON. Some PLC do not need such process, while they use the particular clock pulse generated by PLC.

2:send the data which need displaying to the data buffer and reset the control buffer. For example "MOV #1234" sends constant #1234 to the buffer 211. If you want to display a variable, you can send a particular buffer to buffer 211, and send the data to the particular buffer will make it. 

3: "SFT" can move the data in four buffers from 209 to 212 one bit left and fill the vacancy at right wiht "1". It doesnot need resetting.

4: "SDA" is data output which satisfies the output of "Sink" transistor, when it comes to the "source" transistor, it needs to revert.

5: "SCK" is the output of clock pulse which satisfies the "Sink" transistor, when it comes to the "source" transistor, it needs to revert.

Only process 3 is needed to repeat to deal with the situation of bi-watch or multi-watch. 

4. OMRON drivers for digital panel meter