IMC CANSAS - Mode (Events-Counting)

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200 Measurement Technique

Although the measurement is differential, the input voltage at any of the input pins may not deviate by

more than +10 V or -10 V from the module's reference ground. Otherwise the input amplifier reaches

saturation which can only be reversed after a long time. The differential voltage itself may only be

between -10 V and +10 V. A greater input voltage (maximum ± 50 V to Chassis) can lead to displacement

of the threshold or hysteresis and thus to undesired results. Another effect of the input circuit's

saturation behavior is a switching delay which could corrupt the measurement results.

The inputs are not isolated from each other. They are referenced to the module's ground (housing,

Chassis, Ground). There is a ground terminal provided in the connection plug (in addition to the ground

for the built-in sensor supply voltage).

A reference ground between the encoders and the imc CANSAS module may have to be established, as

well, even for differential measurements.

Please observe the notes under Block diagram .

5.1.3.2 Mode (events-counting)

5.1.3.2.1 Events

The event counter counts the sensor pulses which occur during a single time interval (differential event

counting) or the sum of all events (cumulative event counting). The interval corresponds to the sampling

time set by the user. The maximum event frequency is about 500 kHz.

An event is a positive edge in the measurement signal which exceeds the user-set threshold value.

The derivative quantities displacement and angle measurement have the following settings:

Choice of one-signal and two-signal encoder

Start of measurement with or without "Zero impulse"

Number of pulses (per unit)

Setting the number of pulses:

IncrementalEncoder0x at Index card "Inputs" > Combo box "No. of encoder pulses"

The number of pulses may be between 1 and 999999.

To obtain the greatest accuracy for imc CANSAS-INC4 measurement results over a wide dynamic range, it

is recommended to select an appropriate input range for the task.

Setting the input range:

IncrementalEncoder0x at Index card "Inputs" > Combo box "Input range"

Note that the input range can be expressed in terms of a different physical quantity than the

measurement quantity. For instance, for event counting the input range is expressed as a frequency.

The input range selected states the input range end value. The highest frequency contained in the

measured signal may not exceed this end value. If this maximum frequency is exceeded during

measurement, the system returns the input range end value at the points where the signal is out of

bounds. The input ranges depend on the sampling interval selected and under some circumstances on

the number of encoder pulses.

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