Spectrum Controls 140 EHC 204 00sc - Manual (Page 10)

Counter / Flow Meter Input Module
11
Hardware Features
The Quantum counter module contains a removable Modicon 40-pin terminal block providing connections for
up to eight input devices. The illustration below shows the hardware features of the module.
For quadrature operation, the module configures channels into quadrature encoding pairs. Both channels in a
pair must be configured for quadrature mode. Quadrature encoding reports the same quadrature count value on
the output of each channel.
The module supports these input types:
•
AC (50 mV to 75V peak)
•
5VDC
•
12VDC
•
24VDC
Both rate and count data are simultaneously available to the user. User selectable instantaneous or average rate
modes are supported.
For improved noise reduction, the module has a digital filter that is selectable between 50 kHz and 30 kHz. A
selectable analog 15 kHz single-pole filter is also available for low speed applications.
Module configuration is stored in the PLC memory. Normally configuration uses ModSoft, Concept, and
ProWorks programming software. Details are provided in chapter 3, “Module Configuration.”
Counter Mode
The counter functions of the module include programmable control of the counter, including start, stop, reset,
and preset control and user-defined flags. The module makes the state of input counter levels available to the
PLC, allowing any channel to be used as a discrete input.
Counter inputs can be configured in pairs for quadrature encoding. A total of four quadrature inputs can be
supported to detect up and down count signals. The module has an onboard timer that converts counter inputs
into a rate output. Both counter total and calculated input rate are made available to the PLC at the same time.
The maximum filter frequency for an input signal is 50 kHz.
When a counter reaches its preset limit value or counts down to zero, it sets a limit or zero flag. The counter
supports the following input K, M, R scale factors:
•
“K” used for range scaling; programmable for each channel. ( Count = Raw count / K )
•
“M” used for meter calibration. ( Count = raw count * M / 10,000, Rate = raw rate * M/10,000 )
•
“R” used to scale the rate output. ( Rate = Raw Rate / R * M/10,000 )
In counter mode, the module updates normal encoder and quadrature outputs at <1.5 ms/channel. The counter
accumulator output is available in two ranges. The maximum count total for the noraml range is 65 K. The
extended range uses two data words per channel and counts up to 16 M.