Tisoft analog alarm programming

[Lora]

I'm programming an analog alarm and I think there are 2 ways to do this.  I can use the CMP block and turn a relay on if the value goes LT or GT a setpoint or I can acually configure an alarm using the 128 alarms available within Tisoft.  I know that the analog alarm programming allows for deadband, multiple alarms, deviation alarms, etc but if all I want to do is notify the HMI that an alarm has occured, why can't I just do that with the coil from the CMP block?  Just wondering if it is possible.  Thanks!

[Michael Lloyd]

The analog alarm block in TiSoft (I actually use Workshop but TiSoft works) is a real handy block. Give it a Vflag address and then use Vx.x bit to trip a C bit. I map every single analog into the alarm blocks. I map them consecutively. Ie Alarm 0 is the first AI point on the card, Alarm 15 is the 1st alarm point on the second card. etc If you use 8 point cards the numbering changes. The alarm blocks may start with 1. It's been awhile. I even map the unused analogs to alarm blocks so future added analogs are easy to implement.

The true value of the block is that all of the features of the alarm are in one place. Scaling, setpoint, scan time, etc. So HMI programming becomes easy (easier) and more structured and troubleshooting an alarm or shutdown is very easy. Disabling an alarm or shutdown is easier to program. There are lots of good reasons to learn to use the alarm block in the TI.

I make it a habit to latch shutdowns (so if something blips i can see what shuts something down).  I liked the alarm block so much that I made one for Siemens S7 and the Control Logix PLC when we stopped using the TI (beast of a PLC though) and moved on the S7 and CLX.  

Edited April 29, 2017 by Michael Lloyd