Functional Description - Hengstler signo 721 Benutzerhandbuch

Skilled electrician is, who can judge the tasks deputed to him and
foresee possible dangers, due to his special education, knowledge
and experience and consciousness of the pertinent standards.
The counters may only be opened by trained personnel for settings.
The counter must be "dead" before opening the program switch cover.
The plug-in terminals may only be operated if "dead".
The identification numbers of the plug-in terminals and of the corre-
sponding socket strip must be observed.
Unassigned terminals (NC) may not be connected!
Connection terminals are to be protected by installation!
In order to ensure hand contact safety of the connection terminals, li-
ve wires must be connected properIy to the connection terminals.
The counter power supply is protected by a PTC resistor. In case of po-
wer supply overload the supply is switched off and automatically
switched on again after cooling. While mounting the device, it must
be secured that the requirements, which are asked for the device in
the pertaining standards for safety, are not affected in a negative way,
so reducing the safety of this mount device.
Mounting and assembling of device need observation of the specifica-
tions of the local Energy Suppliers.
Before switching on, make sure that the power and control voltages
are not exceeding the values in accordance with the technical data.
If it is to be assumed that operation without danger is not further
possible, the device must be put out of operation and secured from
unintentional operation! It must be assumed that an operation with-
out danger is not further possible,
if the device shows damages
if the device stops functioning
after a longer stocking period under unfavourable conditions
after heavy strain during transportation.
If by a failure or a malfunction of the device, endangering of men or
animals or damaging of facilities are possible, this must be avoided by
additional safety measures (end switches, protection devices and etc.)
HengstIer Counters are intended for industrial applications.
The mounting environment and nearby cabling have an important
influence on the EMC (noise radiation and noise immunity) of the
counter.
When putting into operation, the EMC of the whole installation (unit)
has to be secured.
In particular, the relay outputs are to be protected from high noise ra-
diation by suitable wiring.
The range of applications for those products are industrial processes
and controls, where the overvoltages applied to the product at the
connection terminals are limited to values of the overvoltage
category II.
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3. Functional description

Count input
Control inputs
Mains supply
In-line switch
strip
Potentiometer
Fig. 3-1 Block diagram of the preset counter signo 721
The basic function of the preset counter signo 721 is the activation of
an output when reaching a preset value.
Depending on the setting(s) of various switches/the potentiometer
and on the external control input status
• the basic function can be interlinked with external events
• further functions can be influenced, executed or blocked.
The programming of the counter and data input is carried out by me-
ans of an integrated keypad.
The following figures illustrate the counter functions in diagrams.
Example 1
Count
Preset P
0
Keypadreset
ext. reset
0
Output OUT
0
monostable
bistable
• Counter with 1 preset
• Activation of output OUT when count coincides with the preset
value
• Adding count
Sach-Nr. 2 721 091; Version 1250100MW
Display
Indicators
Sensor feed
µP
Control output
P 2
Control outputs
Keypad
t
t
t