Data Storage; Versions Of The Preset Counter Signo 721; Counter Installation - Hengstler signo 721 Benutzerhandbuch

Display memory (Display Hold)
The display can be "frozen" by feeding an active level to the dis-
play memory input (terminal 13).
Prerequisite: switch 3 is set to ON.
Continuous count pulses received at the count input (terminal
11) are counted on without loosing pulses. For a different status
of terminal 13 or if the input is not connected, the display will
show the current count.
This functions allows, for example, the count to be read at a cer-
tain point of time without interfering with the counting opera-
tion and the succession of output signals.
0 721 121/122/125/126
Counter advance sense (Up/Down)
When a high potential is fed to termi-
nal 13, count pulses received at the
count input (terminal 11) are added up.
When a low potential is fed to terminal
13, count pulses received at the count
input (terminal 11) are subtracted.
This function allows the counter advance
sense to be controlled.
Note
This type of count up/down should not
be regarded as equal to the operation
with a phase discriminator because vi-
bration pulses are registered as count
pulses.
Keylock input (Keylock)
By feeding a high/low potential to the keylock input (terminal 14), the
counter keys can be locked in several variations depending on the po-
sitions of switch 6 and 7. Please refer also to the tables on page 15.
This function can be used to prevent the program from being modi-
fied and to block access to the counting operation for unauthorized
persons.
Prescaler output (PSC-OUT)
The prescaler output (terminal 15) is an electronic output, the pulse
sequence of which is equal to the converted pulses shown on the dis-
play.
With this output totalizing counters or tachometers without prescaler
can be triggered. The pulse width of the prescaler output corresponds
to a frequency of 5.4 kHz.
The product (input frequency x PSC) must therefore not exceed 5.4
kHz.
Example:
These pulses can, for example, be fed directly to an additional totali-
zing counter in order to register the amount in litres over a longer pe-
riod of time; or fed to a tachometer in order to indicate the flow rate
in litres/unit of time.
Sach-Nr. 2 721 091; Version 1250100MW

4.5 Data storage

In case of a power supply failure all numerical values in the NV me-
mory (non-volatile memory without battery buffer) will be retained
for at least 10 years.
The stored data are displayed as soon as the power supply is restored.

4.6 Versions of the preset counter signo 721

1 preset
2 presets
1 changeover relay
1 transistor output
2 normally open relay contacts
2 transistor outputs
12...24 V DC =,
sensor output
V DC – 2 V/60 mA
Sensor 24 V AC ~
output 48 V AC ~
V DC 24 V/ 100...240 V AC~
60 mA
Up/down count – via switch,
application input with gate
or display memory function
Up/down count – via switch
input, application input
with up/down function
Note
As mentioned at the beginning of this chapter, you should now set
the switches and the potentiometer as required for the specific use of
the counter.
These settings may, of course, be carried out on the built-in "dead"
counter, but it will be more convenient to adjust the dismantled unit.

5. Counter installation

Note
At this point we assume that you have observed the descriptions of
the counter's functions as specified in chapter 3 and set your counter
according to its specific use.
Please note the dimensions in the following dimensioned drawing for
installation of the counter in a front panel.
Fig. 5-1 Installation dimensions of counter signo 0 721 XXX
19/24