PLC5 Alarm structure

Working on a Large batching and delivery system,100's of alarms.
Anybody have any slick method of doing alarms.

Not my program but I like the way it was done and it works
very well. Uses for next loop.

Have never used the FOR or Next instructions. could you elaborate
a little more on what they do for you in this application.

not great

not really that impressed to be honest, why waste so many words of data the alarms could be written across 11 words rather than 165 for a start by using each bit of each word!.
The over complicated FOR instruction could also be replaced by a MOV (move a 0 to each alarm word). This guys way will work but I think it looks a little amateur.

ryan100980 said:

not really that impressed to be honest, why waste so many words of data the alarms could be written across 11 words rather than 165 for a start by using each bit of each word!.
The over complicated FOR instruction could also be replaced by a MOV (move a 0 to each alarm word). This guys way will work but I think it looks a little amateur.

Click to expand...

I couldn't disagree more. I think its very efficent and professionally done. To each his own, I guess.

Christoph said:

Have never used the FOR or Next instructions. could you elaborate
a little more on what they do for you in this application.

Click to expand...

The loop is simply used to turn on a horn and/or light.

Here is how I do my alarms these days. They work on a simple KEEP (latch - unlatch) instruction. This one is a bit different as alarms can be acknowledged and reset locally or remotely dependant on the position of the Local/Remote switch.

The alarms and acknowledges are placed in different channels (or range of channels depending on how many alarms). The bit count instruction BCNT is used to count the number of bits on in the alarm channels and acknowledged channels. One > instruction is used to indicate an alarm is on to flash an indicating light. The other > instruction is used to indicate alarms on > acknowledges on and operate a siren. When the acknowledge button is pressed, alarms on will = acknowledges on and cancel the siren. Resetting the alarms will also reset all acknowledges and sound the siren to indicate there are still active alarms.

Suits me and may be of some assistance. I have tried many ways over the years and found this way is quite simple. Have also experimented with XOR etc but prefer this.

Here's one I did for a contrologix, but the same method can be used in the 5. The number of alarms to process has a bearing on how complicated your routine is. I have used simple bit sets for few alarms, and stuff like this routine for more extensive applications.

I have used a method that dedicates a word to a device. This word can indicate status, control, alarm, and indicate certain things discretely about the device along with an alarm. I always used the 8th bit ofthat word for the alarm. I then had a sequencer at the end of the file with a 2 second timer. The seqeuncer would be as long as the amount of the alarms. If the eigth bit was on while the sequencer rolled through, it would flash a message on the banner of the hmi. In essence, I would have a constantly updating banner that would scroll through the currently active alarms. Very handy. I could also use the sequencer to set the horn on and allow the alarm to be silenced and continue to show the active alarm.


David