PLC5 Analog Ladder

[Mickey]

Where does someone from a South Pacific Island go on vacation?

 

[razal]

Hello - Thank you Mickey, Ron
I went back to my village where my parents are for a week because my kids are having a week school holiday. Overhere, people terms this kind of leave as going for a holiday or vacation.

I'll work more on the SLC 500. But for now however, can you assist me on the PLC5 ladder. Now that we have configure hardware and software wise on the I/O cards, what I should I add to the ladder so that say, an 8mA input (4-20mA range) can produce the equivalent voltage of 2V output on the voltmeter which has a 1-5V range. Do I need 2 ladders or 2 BTW/BTR. I guess we don't need the conversion instruction for the PLC5 ladder ( not as required in SLC500) becuse this is already done during the configuration.

Could anyone give a sample PLC5 ladder program that use the 2 I/O analog cards.

Again thank you

 

[Ken Moore]

Give this a try.

 

[razal]

Thank you Ken for the example. I will try it at the office tomorrow. I believe your example(rsp file) can only be open by PLC5 software.

As a student I'm grateful to you and all that have been my gurus. We have a saying here that one could be a servant to a person even if he has learned one thing from him.

 

[Ron Beaufort]

here's a copy of Ken's excellent example program in .PDF format for those who don't have RSLogix5 handy ...

 

[razal]

Ron,

Thank you for the pdf file. For the moment I'm engage in some other work. By the way the PLC is being used by others for training.

I'm very grateful.

 

[razal]

Dear everybody,

Thank you for your patience and excellent guide. I finally succeeded meeting the first challenge in Analog programming. I managed to configure the I/O cards. When I inject 1-5V into channel 1 of 1771-IFE/C rev 02 input card and using the mov command, the PLC5 is now produce the 4-20mA output from the channel1 of the 1771-OFE2/B rev AB2 output card.

I appreciate if you can guide me step-by-step on how to implement PID control. In my lab I have a simple process loop ie. a dp transmitter is giving out 4-20mA signal (PV) to measure height of a water level in a transparent plastic tank. This current signal is converted into 1-5V by tapping across a 250 ohm resistor. The 1-5V is then injected into a Yokogawa controller. Using a PI control, the controller then gave a 4-20mA output(MV). This output goes to I/P converter to move a control valve. The control valve is at the upstream side of the tank. A pump is used to move the water in the loop.

Now, I wish to replace this Yokogawa controller with my PLC5.
How should I do it - what is the ladder dagram to carry out a P,I,D control; do you need an external 1-5V or 4-20mA signal for SP setting and etc. I knew the basic concept of PID control. Again I appreciate your good guide.

Thank you