IM-P693-02
EMM Issue 2
7
LCR2251 Level Controller
4.2 Supply voltage connection
The equipment must be supplied with 24 Vdc from a SELV (Safety Extra Low Voltage ) power supply. An
external 0.5A semi-delay fuse must also be fitted.
This power supply unit must be electrically isolated from dangerous live voltages and meet the requirements
for double or reinforced insulation in accordance with one of the following standards:
EN 50178, EN 61010-1, EN 60730-1, EN 60950-1 or EN 62368-1.
4.3 Connection of output contacts
Wire the upper terminal strip
1
(terminals 16-23), shown in Figure 1, according to the desired switching
functions. Provide an external slow-blow 2.5 A fuse for the output contacts.
When inductive loads are switched off, voltage spikes are produced that may have a major adverse effect on
the operation of control and measuring systems. Connected inductive loads must therefore have interference
suppression (RC combination) as per the manufacturer's specifications.
4.4 Connecting the level transmitter
For connecting the equipment, please use a screened, multi-core control cable with a minimum conductor
size of 0.5 mm
2
, e.g. LiYCY 2 x 0.5 mm
2
, maximum length 100 m.
Wire the terminal strip as shown in the wiring diagram (see Fig. 4).
Connect the screen as shown in the wiring diagram.
Route the connecting cable between items of equipment separately from power lines.
4.5 Output of manipulated variable Y or connection of actual
value output
For connection, please use a screened, multi-core control cable with a minimum conductor size of 0.5 mm
2
,
e.g. LiYCY 2 x 0.5 mm
2
, maximum length 100 m. Please note the load of max. 500 ohms.
Wire the terminal strip as shown in the wiring diagram (see Fig. 4).
Connect the screen as shown in the wiring diagram (Fig. 4). Route the connecting cable between items of
equipment separately from power lines.
Any item of equipment that you wish to connect to the terminals for the output of manipulated
variable Y or actual value output 4-20 mA must be certified to have at least double or reinforced insulation
to EN 50178, EN 61010-1, EN 60730-1, EN 60950-1 or EN 62368-1. between the current loop and live parts
of the equipment that are not supplied with safety extra-low voltage (SELV).
Important
Do not use unused terminals as support point terminals.
4.6 Tools
Screwdriver size 3.5 x 100 mm, fully insulated to VDE 0680-1.
