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8017171/115Z/V3-0/2019-01/ SICK OPERATING INSTRUCTIONS | VISIC100SF
Subject to change without notice
PRODUCT DESCRIPTION
2.3 Interfaces
● Standard:
– 3 analog interfaces for measured value output
– 2 digital interfaces for maintenance requests or malfunction messages
– RS-485: Either Modbus-RTU or SICK bus to the TAD control unit
● Optional:
– PROFIBUS DP-V0
2.3.1 Analog interfaces characteristics
The interfaces of the VISIC100SF provide 4 ... 20 mA signals. If an error exists on the
VISIC100SF or when the measured value underflows the lower measuring range limit, the
relevant analog output switches to 1 mA. If the upper measuring range limit is exceeded,
the relevant analog output switches to 23 mA.
The following formula shows the relation between the output current and the respective
measured variable:
2.3.2 Digital interfaces properties
If a device error is detected or a measured value is outside the measuring range, an error is
signaled via the malfunction relay. If no device error exists, the malfunction relay is in a
closed state. The relay opens when an error occurs.
2.3.3 Modbus-RTU interface characteristics
see “Modbus-RTU (integrated in the VISIC100SF standard version)”, page 39.
The switch to 1 mA only affects the analog output with a device error. All other analog
outputs continue to output a measured value between 4 ... 20 mA.
The analog interface can deliver a load of up to 500 Ohm.
The refresh rate is ≤ 1.6 seconds.
Messgröße (Gas-Konz. o. Sichttr.) = x Messbereichsendwert
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Measured variable (gas conc. without visibility)
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