Recent content by BigBlock

Im using the cheap relays to isolate the contacts on my plc from the solenoid valves. As for advice.. Lay out your panel in cad/excel/back of napkin before starting. I have an interconnect speadsheet that shows where every wire is laneded. This took a long time but was worth it, especially when...

I tested a similar setup and have the info on a different thread. Another thing to check is that some sol valves need a min pressure to open. If your regulator is set real low that may be an issue. I added a pressure gauge to ensure that the pressure is set consistently. Also be aware that those...

For temp measurements in pipes I just used a compression fitting with the standard ebay "waterproof sensors" and threaded into my rims setup. I've only tested with water but it worked well. I'm using an arduino nano as a cheap I/O expansion module for my plc via modbus. Setup works well but...

I have an arduino talking modbus RTU (rs485) to an automation direct Plc (sending and recieving) If you're interested I can send you the source code. All you would likely need to do is update the communication settings and signal address's.

Yeah when I was a young engineer i was amazed me to see this. I think that it's a disservice to the nuclear industry that there are so many hurdles to upgrading automation that would lead to safer overall plant operation. We can do better than 1960's tech.

In the power gen world we have multiple layers of automated protection. If the primary fails then there's the backup, and both will typically protect prior to the operator taking action. That being said there is still an oh $h;+ button because things happen, but Ive only seen that used once when...

The arduino nano with the terminal block is a great compact package that I use for similar projects (humidity control). It has the same capabilities of an uno (slightly less I/O) and total cost on ebay is about $7 shipped on the slow boat. I am using one in my automated homebrew panel to provide...

I repurposed an old P4 desktop from~2002 for my hmi. You can download igss free 50 or other preferred hmi program and put together a user interface to talk to a dedicated plc, arduino, pi, etc that is executing the automation routine.

I havent looked into the cost of pc I/O lately, but in the past its been a bit pricy. I use an arduino as a cheap I/O expansion for my plc, although if I were to start from scratch I could prob just use the arduino. For around $25 on ebay I have a nano with terminal block base, 5 temp sensors...

Not sure where you purchased from. I've found if you buy a 5 pack of cheap probes from ebay, one will likely have a connection problem like that. I had to throw away one that had intermittent issues after a couple months. The others have been good for over a year now.

Yeah, I focused mainly on the PID section and trusted the rest of your code on the timing aspects without actually going through it. :mug: Since I'm using my PLC for the actual control code I hadn't worried about timing on collecting data from a few sensors until issues arose. I didn't have...

Just a quick lesson learned on the arduino rims using modbus.... One thing I didn't realize about many of the arduino ds18b20 temp sensor libraries(because I never looked) is that they will implement a delay when waiting for the sensor to convert temp. This delay wreaks havoc with the modbus...

I don't think that you will have a problem with the honeywell setup. Make sure to setup the dip switches properly for your operation and purchase a compatible gas valve. There's a good seq of operation in the user manual.

I'm running igss connected to my plc, I don't think it would be too hard to get it talking to an arduino if you needed but I haven't tried. I just use igss to display the process, record data, and provide the interface to change variables. The automation is all done in the controller. I'd be...

Something like this? http://www.automationdirect.com/adc/Shopping/Catalog/Circuit_Protection_-z-_Fuses_-z-_Disconnects/Fuses_-a-_Fuse_Holders/Fuse_Holders,_Fuse_Blocks_-a-_Accessories/Class_RK1_-a-_RK5_Fuse_Holders,_Fuse_Blocks,_-a-_Accessories/R25030-1SR There's also DIN versions as well...