Specifications

113
CREATING MACROS • METERING MACROS
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METERAD
After receiving the analog input voltage on a meter input, it is
converted to a digital integer value. This value is called the A/D (A
to D) value. A macro can read or modify that value. The A/D
hardware has 4096 “bins” that it fills up in proportion to the
maximum input value (typically +10VDC) and the actual input
value. If the input range was set to 0VDC to +10VDC and the
actual input value was +5VDC, then the A/D value would be 2047
((4096÷2)-1).
The METERAD statement is immediately followed by the channel
number inside of parentheses.
Macro Line Example Description
METERAD(5) = 390 [CR] Sets the A/D value of Meter Channel 5 on this unit to 390
METERAD(3) = METERAD(13) [CR] Sets the A/D value of Meter Channel 3 on this unit to
the same value as Meter Channel 13 on this unit
METERCC
The calibration constant of each metering channel is unique and
may be modified manually or by a macro. The calibration constant
is a multiplier that is applied to the input A/D value before being
usable by monitoring software or mathematical functions in a
macro. This way a +3VDC input can be made to equate to 2.1KW
(Kilowatts). The calibration constant in this instance would be
approximately 0.00171 (2.1÷(4096*.3)). For a displayed reading of
50,000 and an input of +8.5VDC, the calibration constant would
be approximately 14.3596 (50000÷(4096*.85)). The .3 and .85 in
the above equations represent a percentage of a maximum value:
3 volts of 10 volts possible and 8.5 volts out of 10 volts possible.
The METERCC value is a floating point value and is entered in an
equation form with METERCC followed by the channel number
inside of parentheses on one side of the equation and its floating
point value on the other.
Macro Line Example Description
METERCC(14) = 2.583 [CR] Assigns the value of 2.583 to Meter Channel 14’s
calibration constant on this unit
METERCC(12) = METERCC(3)/14 [CR] Assigns the value of this unit's Meter Channel 3’s
calibration constant divided by 14 to this unit's Meter
Channel 12’s calibration constant