Siemens SIWAREX WP231, Руководство пользователя

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Connection
6.2 24 V connection
SIWAREX WP231
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Manual, 07/2014, A5E31238908A-02
6.2 24 V connection
The 24 V DC supply voltage is connected by means of the corresponding terminals on the
electronic weighing system.
Table 6- 1 Connection of the 24 V supply
Labeling Function
L + +24 V voltage supply
M Ground voltage supply
6.3 Connecting the load cells
Overview
Pickups can be connected to the SIWAREX WP231 electronic weighing system which are
equipped with strain gauges (DMS full bridge) and meet the following requirements.
● Characteristic value 1 to 4 mV/V
● A supply voltage of 5 V is permitted
The power supply for the load cells is 4.85 V.
The following condition must be satisfied in order to check the maximum possible number of
load cells which can be connected to a WP231:
● Scale operation without Ex interface: (input resistance of load cell) / (number of load cells)
> 40 Ohm
● Scale operation without Ex interface: (input resistance of load cell) / (number of load cells)
> 50 Ohm
Rules
Observe the following rules when connecting analog (strain gauge) load cells:
1.
The use of a junction box (SIWAREX JB junction box) is required when more than one
load cell is connected (the load cells must be connected in parallel). If the distance of a
load cell to the SIWAREX WP231 or the junction box is greater than the available length
of the load cell connection cable, use the SIWAREX EB extension box.
2. The cable shield is always applied at the cable gland of the junction box (SIWAREX JB)
or the extension box. If there is a risk of equipotential bonding through the cable shield,
connect a equipotential equalization conductor parallel to the load cell cable.