Analog expansion module for ML 1500

[advmin]

Good morning Guys,

PLC: micrologic 1500 LRP 24bwa c series
soft: Rslogix 500
We are required to consider the weight of the product in such a way that, when a particular weight is reached, the plc should stop the process.
For that, we are planning to use loadcell, but the output is analog.
I didn't have any analog modules with my plc (7 digital inputs and outputs modules right now).
In the documentation, it says that max of 8 i/o modules can be added with the base.
1. Which analog module should I use?
2. Do I need to configure it manually or just by clicking "read I/O config"
after installing ?
3. Any other suggestions to use analog inputs without purchasing an analog
module for the load cell?
4. I saw a power distribution issue in the documents, Does that cause any
problem if I install the module in the 8th position?

slot no module
1 1769 sdn
2 1769 sdn
3 1769 iq16
4 1769 iq16
5 1769 iq16
6 1769 iq6x (6 i/p , 4 o/p )
7 1769 ob16
8 vacant


cheers.

 

[Puddle]

3. Any other suggestions to use analog inputs without purchasing an analog
module for the load cell?

I've not spent much time on the Micrologix range so I won't confuse things by commenting on that, but I can see two alternatives here.

1. Many load cells have a relay output which can be programmed to trigger at a set point, so this may solve the issue if it's a consistent setting.

2. Monitoring relay to achieve the same as idea 1.
https://uk.rs-online.com/web/p/monitoring-relays/1113090?gb=s

 

[cardosocea]

Does your current load cell amplifier have a network connection? Which protocols does it use? I've done this before with a DH+ to Modbus converter or EIP to Modbus serial converter to get weights into the PLC program (PLC5 and CPX).

If going the analog route it'll be a 1769-IF8 or so.

 

[advmin]

I've not spent much time on the Micrologix range so I won't confuse things by commenting on that, but I can see two alternatives here.

1. Many load cells have a relay output that can be programmed to trigger at a set point, so this may solve the issue if it's a consistent setting.

Thanks for your reply. Unfortunately, it's not consistent and the client needs almost 30 to 50 different weights.Plc needs to act differently for different weights.

f going the analog route it'll be a 1769-IF8 or so.

Thanks mate.no other protocols are available for this one, only the analog route is an option.
So 1769-if8 or 1769-if4 would be the better choice.

cheers all.

 

[alan_505]

Where is your power supply located?, as some analog cards have to within a certain number of modules from the power supply.

From series B on you could have 16 IO modules, I think you then need extension end caps and another power supply for the next bank of IO.

 

[advmin]

Where is your power supply located?, as some analog cards have to within a certain number of modules from the power supply.

Thanks, Alan for the reply.

The 230/120vac power supply is powering the PLC and after referring to the ML 1500 documents, I found that up to 16 i/o can be installed and a maximum of 8 can be installed along with the base/processor and there is a power distribution calculator just before the glossary section in ML 1500 document which will help us to calculate the power distribution required.


cheers, all.

 

[OkiePC]

Years ago, I used a Hardy Instruments 1769 module designed for weighing applications that did a ton of the work for me and wired directly to the load cells. Mine was a CompactLogix PLC, but I think they can be used with the ML1500 too, just without the handy dandy UDT/AOP.

https://www.hardysolutions.com/hi1769

It's more expensive than a regular analog card, but can pay back some of that time in reduced code development. My application was an inline case check-weigher, (load cells affixed underneath a short, moving conveyor belt) so it needed to be fast and that module is awesome for that sort of thing.

I used their C2 series load cells and summing board too, which made setup and calibration a cakewalk.

 

[widelto]

OkiePC: ++++++
I'd add ML1500 is obsolete, so I will not spend any money on it.
C2 technology from Hardy is excellent, they even have a network exclusively for load cells up to 32.
I forgot to mention that if I were in such situation, I would move to compactlogix.