Get Counter command's parameter list does not show power total (summation) tags from energy/power monitoring modules

Applies To:

PAC Control Professional
PAC Control Basic

Versions Affected:

R10.4a to R10.4c

Resolved In Version:

R10.5a (Also requires a groov EPIC/groov RIO/SNAP PAC firmware update. See Resolution for more information.)

Symptoms:

For the following modules, when using PAC Control to configure the Get Counter command, PAC Control does not list the supported power total (summation) channels in the argument 0 (From Point) drop-down list:

GRV-R7-I1VAPM-3
GRV-IVAPM-3

Workaround:

Until the updated firmware is available, you can read accumulation and summation values with either Get Counter 64/Move commands or directly from the memory map with a Read Number command.

With Get Counter 64/Move Commands

Select from one of the following options (as appropriate for your application):

Option 1: To read mWh as a 64-bit integer, use the Get Counter 64 command. This requires PAC Control R10.4a (or higher) and either groov EPIC firmware 3.3.0 (or higher) or PAC firmware 10.5a (or higher). This is how the data is natively accumulated on the unit and has the best resolution, and eliminates rounding errors (compared to floating point numbers). This method allows reading much larger accumulated energy values than using 32-bit integer or 32-bit float.
Option 2: To read kWh as a 32-bit float, use the Move command. This requires PAC Control R10.4a (or higher) and either groov EPIC firmware 3.3.0 (or higher) or PAC firmware 10.5a (or higher). Floating point values will lose resolution if the value becomes too big. For details, see the "Using Floats" topic in the PAC Control User's Guide (form 1700).
Option 3: If you want mWh as a 32-bit integer, you can use Get Counter 64 (see the first option above) to store it in a 64-bit integer variable and then use the Get Low Bits Of Integer 64 command to move the lower 32-bits into a 32-bit integer variable.

For larger accumulated energy values, use option 1 (64-bit integer).

From the Memory Map with Read Number Command

Use the Read Number from I/O Unit Memory Map command to read the counter value directly. As described in the data sheets for the modules, the accumulation and summation values are available in three different data types, each in its own spot in the memory map. To access the correct spot:

Calculate the channel's base address as follows:
```
0xF0260000 + <slot number> * 0x1000 + <channel number> * 0x40
```
Note: The "0x" prefix indicates a hex value.
Add the offset for the value you want:
- 0x00: 32-bit IEEE-754 float (accumulated or summed energy usage in units of kWh (or kvarh or kVAh))
- 0x20: 32-bit signed integer (accumulated or summed energy usage in units of mWh (or mvarh or mVAh))
- 0x24: 64-bit signed integer (accumulated or summed energy usage in units of mWh (or mvarh or mVAh))

Examples:

Reading mWh (32-bit signed integer) from channel 31 (0x1F) on a GRV-IVAPM-3 module in slot 3:

Calculate the channel's base address: 0xF0260000 + (0x3 * 0x1000) + (0x1F * 0x40) = 0xF0260000 + 0x3000 + 0x7C0 = 0xF02637C0
Add the offset for 32-bit signed integer, which is 0x20: 0xF02637E0

Reading kWh (32-bit IEEE-754 float) from channel 57 (0x39) on a GRV-R7-IVAPM-3 module (a groov RIO EMU). Note that for groov RIO EMUs, the slot number is always 0.

Calculate the channel's base address: 0xF0260000 + (0x0 * 0x1000) + (0x39 * 0x40) = 0xF0260E40
Add the offset for 32-bit IEEE-754 float, which is 0x00: 0xF0260E60

Resolution:

To completely resolve this issue, you will also need to install a firmware upgrade:

For groov EPIC or groov RIO: 3.5.0 (available Q1 2022)
For SNAP PAC: 10.5a (available Q2 2022)

Questions?

Contact: Opto 22 Product Support.
Phone: 800-835-6786 or 951-695-3080
Email: support@opto22.com

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