I want to be able to use a PLC to drive the function of this pump. The batch volume will be fixed and I want to start the batch via a PLC digital out. Question - once the start signal is received by the pump (100 ms) does the contact condition need to remain closed or does it start the pump and continue to run the preprogrammed batch volume to completion? I am envisioning the later is the case and am thinking the reset function would be applied by the PLC programming, i.e., a 3 second digital on condition once it is known the batch has completed. Does the preprogrammed volume remain fixed until it is changed vis the control knob?
Hello jbrooks,
Welcome to the DigiKey TechForum.
I’m not familiar with this programming, but hopefully one of the engineers can add to this post with their knowledge and recommendations.
Hello @jbrooks
From what you have explained it sounds like you are looking to have an input signal that will start a pump, that will run a preset amount of material and then turn the pump off back off. how you would do this would depend on the PLC IEC 61131-3 standard languages that are avaliable on that PLC.
Using ladder logic as an example there are a couple different ways that you can do this, you can use a latching circuit, or a pair of set and reset coils. For both of those circuits you would need 2 different inputs to control the digital output to the pump.
A latch circuit in ladder logic
A Set/Reset Coil pair.
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The PLC will manage input/output timing functions according to its programming—whether it updates the output based on the current input status or completes the timing cycle before checking the input. However, for a basic circuit, a Timed Delay Relay or a Process Temperature Controller might be simpler and a more suitable solution than using a PLC.
Thanks guys. I should mention I have a full Contrologix with spare I/O and an integrator available at a water treatment plant where I am thinking of this application. The question is more for clarity on how this pump functions - the start bit from the I/O card would start the pump and the pump would then run until the set volume is achieved? And, if so, once the set volume is achieved does the cycle reset itself or does it require a 3 second on condition to reset for the next batch. If it means anything, this function would only happen a few times a week.
@jbrooks ,
Unfortunately DigiKey does not currently carry Allen Bradley products or the pump you are referring to in which case we are unable to support those products. You may want to check with a distributor online which carries and supports their products.
Apologies we cannot be of more assistance on this.