How do you read the counters out of a Zetron Model 1708 rtu?

[RadioTech1]

Using a Zetron 1730 Controller and a Model 1708 RTU and need to read a counter that is connected to a water flow meter sensor.

I know the sensor is working, and I am running it to a digial input on the 1708 in status mode to use the counter for that input.

Using the zetron diagnostic program connected to the 1730 controller, I can poll the remote rtu and see the counter incrementing, so I know Im getting the count into the office

I can not find where or how to get lookout to do this. I am sure its there, I have looked in help, developers manual and I must be blind.

I realize it will have to be scaled and formatted but right now Id just be happy with getting the count into lookout.

Thanks for any help

[Ryan.S]

First you need to select a lookout driver object to do the communcation. For example, we can use the Modbus object to communicate with the Zetron PLC through Modbus protocol.

Here is another thread about a similar problem.

http://forums.ni.com/ni/board/message?board.id=190&thread.id=1795

I also suggest you to contact Zetron tech support. Ask them for how to configure or setup the PLC for modbus communication, and the detailed Modbus master's parameters.

After you setup the modbus communication, you need to know which modbus address is the one for the counter.

[RadioTech1]

Ok, Maybe I did not clearly explain things.

This is a functioning system, lookout, Zetron 1730 Controller and model 1708 rtus.

And we are using Modbus

I want to GET the count from the digital counter on digital inout #8 of one of the 1708's.

In the Zetron book it says the address for that counter is 42081 for the value and 42084 for the period.

But, in the Model 1730 book it says that the address is 43029 and 43031.

Zetron says I want to read 43029 and 43031

So, I was thinknig I would use the Integral Object for this, but now am not sure.

Is this any better for you?

Thanks

[Ryan.S]

To get the counter data, just create the Modbus object in lookout, and read the address 43029 and 43031. Take a look at this KB, especially part 2.

http://zone.ni.com/devzone/cda/tut/p/id/3381

I don't think you need the Integral object. If the flow meter output is, for example, how many gallons per minute of the water flow, you need use the Integral object to calculate the total number of the water flow during a period.

But your current input to lookout is the counter, which counts the digital pulse. It is already the total number of the digital pulse during the period. After you get the counter data into lookout, maybe you need further scaling to get the tatol water flow, and maybe use the period to calculate the flow rate.

[RadioTech1]

Ok, Thanks! Reading the counter just fine. Moving on to the scaling.

Thanks again

[DEQ]

Can you share what 'object' you used in Lookout to read the counter?  Did you leave the input as 'status'?  Any help would be appreciated!    Thanks 

[Ryan.S]

He is using the Modbus object, as the rtu supports Modbus protocol.

[DEQ]

Spoiler

Ryan,

I created a Modbus object for the counter.  Zetron says that queries to read a counter must request all associated registers or an illegal data address will be returned.  The counter I'm trying to read is:  count address range 43061-43062 and the period address range is 43063-43064.  I just want to 'read' the counter, I don't need the period.  So, do I have to combine 43061, 43062, 43063 and 43064?  If so, what is the easiest way?  Please give example.

thanks for you help

[RadioTech1]

1.  Create a Modbus object with the correct comm parameters and address of the 1708 in question

I set the "poll="  to poll the counter when then WELL shuts OFF  (an expression for the WELL on/off indicator will work)
I then also set the "pollrate=" to 10:00 minutes (just in case the WELL off command got missed -this is on a trunked two way radio system)

2.Then under Modbus member configuration:
add the following addresses's ; D43201, D43022, D43023,D43024 for zetron digital input #6

Then create an expression D4301/2*1000   (Counter /2 (divide by 2) *1000 (for counting in thousands of gallons)
The divide by 2 is because the zetron counts the leading upward going pulse AND the trailing downward pulse

Then you can put the count on the screen  using a guage and using the expression above as the signal.

It works fairly well, the zetron book is not very clear on this.

Ignore the 1708 manual use the chart out of the 1730 controller manual page 22 table 10 Counter Address

David English

[DEQ]

David,

Thank you very much for your information, I will try it tomorrow and let you know how it works.  You saved me hours.     Don