Created Date: April 29,2001

Created by: Des

I'd like to see a 1 shot latching relay, ie;

one pulse on, one pulse off using the same contact to pulse it. This would be less cumbersom than using set and reset instructions.

Can the dl250 cpu bottom port (15 pin) be used for the dv1000? it is a real pain having to remove and replace the programming cable all the time whilst programming.

I'd like to see a better explanation of the use of non volatile memory than in than in that 1 page explanation recently. This needs to go into the manuals now. Does the 250 have any n.v. memory?

Created Date: April 30,2001

Created by: KPrice

Des, the following simple code may help you with your "latching relay " application. Connect your single contact, for example X0, to a counter, CT0. Connect the counter contact, CT0, to the counter reset. Set the counter preset to K2. Connect an equal instruction contact, CTA0=K1, to your output, Y0. Your input, X0, will then toggle Y0 on and off. Yes, the bottom port may use RS232C to connect with DV-1000. Critical data, such as V, C, CT, S, T may be retained on battery-backed-up RAM on power loss using the optional battery, enabling the battery and setting the retentive range to include your data. The program is stored on n.v. memory, flash for 250, EEPROM for 240. I hope this may be helpful.

Created Date: May 02,2001

Created by: bcarlton

As long as we 're giving favorite methods of developing a toggle... First I one-shot the input (PD).

I0 C0

---]

Then the following develops a toggle in C1

C0 C1 C1

---] / /

Created Date: May 05,2001

Created by: Des

Your cct is great bcarlton but if i could design it it would look like this:

I I---------------(LCR1)

X0

I I---------------(Y0).etc

LCR1

where LCR = latching control relay

xo toggles once LCR1 energises and remains energised

x0 toggles again LCR1 de-energises and remains de-energised and so on..

Im just after a new instruction to be created

so as to be less cumbersum than all that other boollean, rather than create it all myself.

Created Date: August 03,2001

Created by: rsdroran

THe idea sounds good but doesnt follow true to what happens electrically. I know that a plc simulates alot of things but an input still represents either normally open or closed contacts (to me anyway). To me plc instruction has to follow ( or replace ) physical hardware and at this time I dont know of a normally open contact on a button( or any device) that can latch and unlatch a relay. A single device ( button etc ) can use both open and closed contacts and be wired thru a relay to latch and unlatch. I am new to DirectSoft code but have used AB alot and they have latching outputs and the use of ONS ( one shots ) but the code still required using XIO and XIC for the inputs. I am real new to this forum so dont know how to make the drawings yet, but I think bcarlton displayed it best.

Created Date: August 06,2001

Created by: bcarlton

Two notes:

1. While the PLC provides a simulation of hard electrical logic, there's no reason why it can't go way beyond that. Show me a real world single contact that causes a whole bunch of arithmetic operations to take place. I think a single toggle command would be great (see other posting on suggestions for new commands.)

2. As far as posting a ladder diagram, when you begin to write your post click on the "UBB Code Is ON " note to the left side and read down to the bottom.

Created Date: August 08,2001

Created by: rsdroran

I agree no single device does anything, not like the plc, it simulates a multitude of hardware devices but the point I was trying to make is that the further away from real life devices the harder it is to understand the logic. My point was you cant make a single PB using NO contacts (example) do both start and stop without some other device. The PLC made using arimetic functions simpler too, but they still follow what hardware devices did even tho simulated within the plc. I would like to see alot of functions changed but then you have to change the laws that guideline how electric current flows. All this may make it simpler for the programmer, but what about later on when another person has to deal with what is written and possibly doesnt follow the reasoning or understand that this kind of function is allowed? I still have to deal with pure relay logic on a daily basis so not sure I want functions added that deviate too much. For some of us following the simulation and learning the different languages, formats, protocols etc are enough.

Improve but dont deviate ie follow the KISS principle.