SLC05 and 1746HSCE

Good afternoon, i have been reading some postings and wanted some clarification from some of the AB experts on this site.

First question, i take if from what i am reading that there is differences between 1746-HSCE and 1746-HSCE2 and that one is not an exact drop in for the other. Am i correct in understanding that?

Second I also take it the HSCE2 is probably the newer model since it has the number 2 after it?

Third, i have a 4 slot base, with 1747-L541 CPU and 1746-HSCE, am using RS Logix 500 v7. Have been trying to configure the unit so that i can use the outputs and also use the high speed quadrature encode in, but it does not like something, just not sure what, i am sure it has to do with configuration but being i have never configured one of these HSCE units before thought maybe someone can give some guidance on it.

When i went in i configured all my board, cpu is in slot 0, hsce is in slot 1, 16 point input module in slot 2 and analog output card in slot 3.

So I am wondering if my version of software being older is what is causing the issue of me not being able to get the unit properly working or what.

Any help or pointers greatly appreciated. And no my company does not have a support contract with AB, although i would like them to.

The "2" is the more modern module, and it is not a drop-in replacement for the original 1746-HSCE.

The 1746-HSCE has just one high-speed counter circuit. The 1746-HSCE2 has 2 or 4, depending on how you set it up. There is a module comparison at the end of the -HSCE2's User Manual.

Both modules are notoriously tricky to set up. You really just have to start with the hookup diagram and the User Manual.

There are some good "minimum configuration for RATE/SEQUENCE/RANGE mode" documents in the RA Knowledgebase, but those documents require a TechConnect subscription.

So these units are notoriously tricky to set up. but can i ask once they are set up are they reliable or are they still finicky?

Just asking so i know if its worth trying to set up?

Next can u post any help files on setting this module up?

I am not an expert in programming the slc but i can do modest things. i am wonder what they mean when they say register M0e,1 i know N and I and Q and T and such but unfamiliar with this.

Any help or references or thoughts greatly appreciated

Ken Roach, i am not sure if you can answer these questions concerning the 1746-HSCE but if not maybe someone else can.

First off i have been able to get the unit to work, but in reading it would appear to me as though the inputs for the encoder, are connected thru a opto coupler, and in order to get proper operation you need to connect A and A not, B and B not, etc. would you say this is correct?

I ask this because in the examples given in the manual it shows a single ended encoder but uses either pull up or pull down resistors so that shows that you need both.

Second if the drawing in the book are correct then what exactly is the dip switches for? they show they are to change between single ended and differentual input, so one would think that AB would make it if you turned on single you would not need the resistors nor the connection the NOT input. And if you turn on differentual then you would use the NOT inputs. But that is just my humble opinion.

Third exactly what is the purpose of the switches they dont show any examples with the switches turned on all of the examples show the switches in the off position.

Thanks for taking the time to read this and i hope someone can answer these.

I have used them for well over 25 years and I find them to be very reliable. What I primarily use then for is metering liquids into a batch. The input comes from a pulse meter (1 pulse = X lb or X gal.)
I unlike many others I did not find them hard to setup. You just need to stop and think about what you are doing and have plan.
A few things that may help
Read the manual, you may have to read it several times to grasp what’s in it.
Do not try to copy the HSC data or do any math functions on the input data while the counter is running you will never get an accurate reading that way the HSC count is way to fast for that.
Use the counters programmable outputs to control the valves or other control device, do not try to it in the ladder code there again the ladder executes much to slow to get accurate results. You will be disappointed with the results.
If you need manual control of the output. You can still use the ladder code to turn the outputs on or off using the manual output in the ladder.
If you expect more counts in than the counter HSC register can hold than you need to set up set up the counter as a ring counter with the rollover value set at a nice round number like 100,000 then set up one of the programmable inputs to be on at counts 0 – 50,000 and off at 50,001 to 100,000.
Then in the ladder code setup a add instruction to add 100,000 to a float type memory address with one shot every time the input goes from false to true. Just be sure that you use a ONS in add rung so you get the correct counts. This will give you plenty of time to do the math and not lose any data. You can only do a true total count with the counter stopped or running very slow. The HSC counts the pulses whenever the counter is enabled and the HSC is much faster than the scan time of the PLC. So from one scan to the next the counter may increment an additions 1000 counts or more if you try to read them in the ladder code you will miss the data. If you need to know direction than use 2 of the programmable inputs programmed to offset by 25% of the total counts on 25,000 – 75,000 counts. If 1 is true before 2 than you are counting up if 2 is true before 1 than you are counting down just like an encoder.
I have seen many people try to read the HSC data in the ladder code and do compares or math functions directly with the HSC data with poor results.
I hope this helps

It has been many moons since I used one of these beasts but I seem to remember that you are supposed to use the resistors if you are using anything other than TTL voltages on the interface. I also remember using them with HTL single ended encoders before finding about the resistors so maybe they only improve the noise protection?

Setting them up is not so bad now because there are Wizards built into the software to configure the M files but still a **** to do.