A Simple Modicon 984 Timer Question

sanger

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I'm sure this is a very simple question but what is the attached logic snippet doing? I suspect that it's implementing an on-delay / off-delay timer but I'm not quite sure.

According to the Modicon documentation the upper output if a Timer is on if TIMER = PRESET and the lower output is on if TIMER < PRESET but applying that to the logic doesn't doesn't produce the expected control.

Any ideas?
 
Been a long time since I did Modicon (Taylor), but I'll try to answer. The top output is on if timer is enabled, it continues the rung for additional uses. The bottom is the timer output after the set time has elapsed.
 
The way a Taylor timer works is the bottom node on the right is true until the timer is finished timing. So in this case the second timer will not have enough time to complete. It is set to 150 on the top node which is False. The first timer is set to 55 it times out first and turns off the bottom node thus turning off the "power" to the second timer ... the top none of it.

Top node true at completion of timing
Bottom Node False at completetion of timing

What is interesting about Taylor a Timer can be used off of the power rail using the bottom node to power contacts etc in a pinch.

I done Modicon/Taylor for years.
 
From the instruction help for Modicon 984.

ModiconTimerNXTHelp.JPG
 
With a modicon timer there is always power flow from the bottom output side of the timer, if it has not timed out. There is no need for power flow from the left side to right side. The timer could be in the middle of the page and still give power flow out the bottom. Thus turning an output on.

Pat
 
elitheei said:
The way a Taylor timer
Click to expand...

Taylor was a programming package not a programming language or command set.

The language in question is 984 Ladder Logic.

It makes absolutely no difference what programming software you are using, the commands for 984LL all identical.
 
O my Good Ness sorry for the miss spoken word. I failed english, but passed hard work! Sorry if I mislead anyone with my mistake there. But I hope the guy got point on how the timer works. LOL

ELI ....weak on AB ...Killer on Modicon ...Raised on 984.
 
elitheei said:
O my Good Ness sorry for the miss spoken word. I failed english, but passed hard work! Sorry if I mislead anyone with my mistake there. But I hope the guy got point on how the timer works. LOL

ELI ....weak on AB ...Killer on Modicon ...Raised on 984.
Click to expand...

Not a major deal, but the Modicon name is now also being used for IEC programming (in Unity and Concept) and Taylor has not had 984LL software for almost 10 years now (so many new programmers have never heard of it). I often see people wondering if their program needs to be changed because they are switching from Modsoft to ProWorx32. Then there are those that try to answer a programming question using IEC commands instead of 984LL ones.
 
Well I been out of the Modicon world for about 6 yrs now and sure do miss it. My world now is all about AB and it a new animal. I could program anything in the Modicon family in my sleep. Now at near retirement age I'm scratchin' my head asking some what dumb questions to my brotherhood on here hoping someone will lend me a helping hand.

But a new challenge has been fun and ladder is ladder just got to learn the odds and ends.

The HMI's I struggle with went from TCP to AB. That is a new world there ... night and day ... but the old man will make it.
Dog
 
Patrick said:
So which do you prefer, Taylor or Proworx32?
Click to expand...

I learned 984LL on DOS based Modsoft. I have never felt comfortable the DOS based Taylor. I have always preferred any DOS based (keyboard conrolled) to any Windows based (mouse required) ladder logic software.
 
Patrick said:
With a modicon timer there is always power flow from the bottom output side of the timer, if it has not timed out. There is no need for power flow from the left side to right side. The timer could be in the middle of the page and still give power flow out the bottom. Thus turning an output on.

Pat
Click to expand...

That was the key to solving my confusion. I was assuming that "No Inputs" = "No Outputs"
 
elitheei said:
What is interesting about Taylor a Timer can be used off of the power rail using the bottom node to power contacts etc in a pinch.
Click to expand...

Interesting, I've been been in a spot where I had used all my access to the power rail and had to split a network. Never thought to use a timer out in left field (right field?) to create a new power source. Learn something every day. Thanks Dog,

Brian.
 

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