Created Date: October 19,2016

Created by: scotbirmingham

I have a Red Lion HMI connected via ethernet to a Do-More PLC.

On the HMI I have a NO momentary button which triggers a discrete input X104 on the PLC. This is intended to start a pump. There's also a NC momentary to stop the pump which triggers X105. Additionally, the HMI has an indicator light which turns on with Y1.

The pump runs on an input signal 4-20 mA and has no enable/disable function. R4 later gets scaled from 0-100 to 0-4095 for my WY output to the pump. There's also a check on the tank to make sure it's ready for the pump to start. That's a 4-20 mA signal that has to be above a value and is stored in R1.

Here's what the code looks like.

R1 X104 X105 100->R4

------|>|------| |------| |------(MOV)

R4 Y1

------|>|------------------------(OUT)

Assuming that R1 is in range, when I hit start, the do more immediately enables Y1 and the pump starts running. However, there's a 1.5 - 2 second delay before the light on the HMI turns on. Same things happens when I push stop. Pump stops immediately but the display takes a long time to update. I 've always heard you should use the PLC for control and the HMI for display and user input but the only way I can get the buttons to change quickly is to control the logic in the HMI in a background program. I 've tried reading the Y1 and R4 tags directly, reading an internal tag tied to Y1 via a code block, reading an internal tag constantly being set to Y1 in a background program. They all have a similar delay. Is there a good way to get quick information from the PLC? Thanks.

Created Date: October 20,2016

Created by: Mike Nash

I have only messed with the Parker SSD version of this but maybe you have something set to read only periodically?

The Update Policy property is used to define how the block updates. The default

setting of Automatic will cause read blocks to update continuously, and write

blocks to transfer only those values that have changed. A setting of Continuous

will cause all blocks to update continuously. A setting of Timed will cause all

blocks to update at the rate defined by the Update Period property, with the

entire contents of a write block being written each time.

Created Date: October 21,2016

Created by: Adisharr

At one time I had some lag issues with a Graphite series HMI a Do-More. Ever since then I switched to Modbus TCP for everything. I don't use any of the Do-More drivers. I bulk copy all my I/O into Modbus address and go from them. That solved every lag issue I had.

If you go Modbus, everything will be almost instant.

Ether way, contact Red Lion support directly. They are familiar with Do-More and are usually very helpful.