Hi,
Has anyone connected a Powermonitor 3000 via DeviceNet to a DeltaV DeviceNet card?
I'm not sure how to read parameters from the Powermonitor. I got up to the part where I added a new DeviceNet Device on my I/O. When I create a new DeviceNet Signal, I'm not sure how much to offset for Average Current, Line-voltage, etc.
I'm looked through the Powermonitor 3000 manual and I'm a confused how to translate the CSP, AIP Assembly into byte offsets in DeltaV.
Please help, thanks in advance
Modules can read a read-only parameter for a DeviceNet device. The parameter_specifier component (leading zeroes are not required) consists of the class code, instance, and attribute ID.
Cnnnnn/Innnnn/Annn
where:
For example, for a device named PDT1 at address 16, a module can use the following path to read the parameter at class code 1, instance2, and attribute ID 33 as float:
/&PDT1/C1/I2/A33/FP
Tip DeltaV reads raw values stored by a DeviceNet device. For a parameter stored as an integer, but which needs to be displayed as a floating point value, you may need to add either a Divide (DIV) function block or other expression to appropriately scale the value. For example, if a value is stored as the unsigned integer 47, and the meaning of the value is hundredths of amps, you can specify that the value be divided by 100 to force it to display as 0.47.
The EDS file may contain information about the data length, but it does not contain any information about the data itself. The user maps the data to signals which have no semantic meaning to the system. For each signal you can specify signal direction, data type, byte offset, scaling, and the bit pattern.
You can configure a device's signals at the DeltaV Explorer library level and at the physical network (I/O) level.
Library Configuration - To save engineering time for similar devices, create default signals in the library. Configure the signals that are common to all the instances of the device. When the default information is complete, drag the device revision to a DeviceNet port on the network.
Physical Network Configuration - Select the device at the I/O level, select New DeviceNet Signal from the right mouse menu, configure the signal, and then assign a Device Signal Tag (DST) to the signal. (Select the signal, and select Assign Device Tag from the right mouse menu.)
The input/output sizes for the device are configurable. The DeltaV system uses the default input/output sizes if available in the EDS file; otherwise, it sets the input/output sizes to 0. Refer to the device documentation to determine the input/output sizes and to determine how to map the data to DeltaV signals.
Niklas Flykt
Klinkmann Oy
Key Account Manager safety products
nikfly@gmail.com
I have set these up many years ago and only remember 2 things about them. The ones I setup were Rev 2, so things might have changed since then.
1) Setting up the I/O Assembly was painful. (We eventually wrote a vba macro that would setup the powermonitor from excel through rslinx)
2)If you setup the powermonitor to give you data back as Floating Point, Keep in mind that you'll have to convert it from "Big-Endian" to "Little-Endian" and then reassemble the floating point. (Search for IEEE 754 for more floating point information.)
Good Luck!
In reply to Tyler Anderson:
Thanks!
Niklas - When you say a module can use the path "/&PDT1/C1/I2/A33/FP" to read the parameter, I'm not sure how do add this, since the path is longer than 16 characters and has a special character.
Tyler - Thanks for the hint! Though I'd like to try to avoid doing any VBA macro and using RSLinx, as I don't think we'll be using it.
In reply to clarencekwan:
The /&PDT1.... reference was new functionality in v11 so if don't have v11 you won't be able to use this.
For help on this:
v11 Books On Line -> Configuration -> Modules -> Access Intelligent Field Device Diagnostic Data
Regards,
Matt
In reply to Matt Stoner:
Thanks Matt.
I am using v11. I just changed my module and it's able to take in path's as parameters.
Had to make a 'Internal Read Parameter' with 'External Reference' parameter type.
At least I think this is how it's done.
Not knowing so much of these equipment..just googling and reading articles.
Almost everywhere they write that "it´s a pain in a## to setup" the communication.
I got the picture that you have to write to a output parameter the value you want to recive. (or then it´s steping automatic?) eg. first word is 24 could stand for voltage, and the other word is the value for that parameter ?