Humidity PLC Question

8keith8 · Apr 23, 2014

I currently work in a furniture factory and we are having problems with humidity. Our humidifiers and humidity sensors currently have no automation and are either on at all times or off.

Currently I am looking at using these probe sensors
http://www.monarchinstrument.com/pdfs/THP-W.pdf
Using these sensors I plan on making a program that turns the humidifiers on/off depending on if the humidity in that part of the plant is in its designated humidity range.

Was wondering if anyone has ever dealt with a problem similar to mine and if so what PLC they used and they're experience with it.

8keith8 · Apr 23, 2014

At this point I am wondering if they're are any wireless humidity sensors out there that I can hook into the PLC.

Lancie1 · Apr 23, 2014

You can certainly use a PLC or a smart relay for this job, but you can also do it with a humidity sensor controlling a contactor that controls power to all the humidifiers in that section of the plant.

If you use the Monarch THP-W humidity probe, you will need a device that will accept milivolt signals in the range of 0 to 1000 milivolts. Most PLCs can only do that if you add a Milivolt Input Module. It might be best to find a humidity sensor with humidity controller that has a settable ON/OFF output that you can use to operator a contactor to turn your humidifirers ON and OFF.

8keith8 · Apr 23, 2014

At the moment we are looking at having 8-12 Sensors in various parts of the plant. I looked around online and saw that most of the wireless ones just don't have the range needed for a big plant like ours.

At the moment I am thinking of using the PLC because its what I am personally familiar with. Currently there is no level of automation at all. This is the problem in an nut shell.

Currently we are having trouble with the humidifiers being on but the fans are not actually spinning so we are looking for a way to automate it all using PLC. The goal is to have a humidity sensor and a velocity sensor on each humidifier and then using the information to turn them off/on depending if they are in our acceptable RH% range. Also a display to make sure that all of the fans are spinning at an acceptable speed.

colts fan · Apr 23, 2014

Have you tried Omega Engineering @ omega.com

Dravik · Apr 23, 2014

If you google, Modbus TCP and Humidity sensor, You'll get a few hits. The only ones I've used are probably far far overkill for what you want to do(Vaisala).

Lancie1 · Apr 23, 2014

Have you tried Omega Engineering @ omega.com

Yes, you could use your Monarch THP-W Humidity Sensor as a 0-to-1 Volt DC input to the Omega Wallmount Process Controller Catalog Number CNi8C22-EN ($490). This controller has various input and output options, including solid-state relays, or RS232 communications network output. Omega also has a process controller that has an Internet interface output option.

Lemming · Apr 23, 2014

Sounds like your fans are controlled from a central point (MCC ??) and the humidifiers locally ?? How big a Factory is it, can you justify wiring the humidity probes / controls back to the fan control point and have a single PLC, or Remote IO and IP ??
The 1 V output from the humidity sensor isn't an issue as long as your input isn't low resolution.. I've never used them, but have been tempted to use "powerline" IP adaptors across the mains in leiu of having to install Cat6 cabling.

shooter · Apr 25, 2014

they should be steady all the time so control is not needed, just have a humidistat to switch on humidifier.

another cheap way is by using arduino with a shield and a relais.

if schoolproject: use a sensor with current output, and local controls, find a way to communicate with control room to show values, and settings. now only simple signals have big distance
another way is using small hoses and a vacuum pump, some valves etc.

shooter · Apr 25, 2014

powerline internet does not work in industrial, only within one phase houses.

Lemming · Apr 25, 2014

shooter said:
powerline internet does not work in industrial, only within one phase houses.

Someone is thinking about it....

http://www.maximintegrated.com/datasheet/index.mvp/id/6514

Getting the adapters on the same ø would be the easy bit. I was working on a clarifier bridge a few years ago and had a monster rotary collector to get a lot of signals back to the plant... Considered a home plug for that with IP IO on the bridge... Chickened out though and went wireless...

8keith8 · Apr 25, 2014

Lancie1 said:
Yes, you could use your Monarch THP-W Humidity Sensor as a 0-to-1 Volt DC input to the Omega Wallmount Process Controller Catalog Number CNi8C22-EN ($490). This controller has various input and output options, including solid-state relays, or RS232 communications network output. Omega also has a process controller that has an Internet interface output option.

Essentially the boss man wants to be able to control everything from home as well, so a good interface that's accessible via internet is a must.

glenncovington · Apr 25, 2014

What is your budget? I have been using the TriLogic nano10 PLC with some success. It comes with Ethernet port and webserver built in. I am currently working with the Advanced HMI Modbus TCP driver to created a usable PC based HMI for the system. For the sensors try www.temcocontrols.com . They have humidity and temperature sensors that communicate via Modbus RS485. Then nano10 has RS485 and can be the master reading in all of the values.

Humidity PLC Question

8keith8

Member

8keith8

Member

Lancie1

Lifetime Supporting Member

8keith8

Member

colts fan

Member

Dravik

Member

Lancie1

Lifetime Supporting Member

Lemming

Member

shooter

Member

shooter

Member

Lemming

Member

8keith8

Member

glenncovington

Lifetime Supporting Member

Similar Topics