6
2.3.3) Constant resistance STOP input
It enables the connection to the control unit of devices with 8.2K
Ω
constant resistance (e.g. sensitive edges)
The input measures the value of the resistance and disables the manoeuvre when the resistance is outside the nominal value
The control unit is supplied with 8.2K
Ω
resistance connected to the input, which simulates the resistance of the devices even if the input is
not used; the resistance must of course be removed when connecting a device with 8.2K
Ω
output.
Also devices with normally open “NO” or normally closed “NC” contacts, or multiple devices, even of different type, can be connected to the
constant resistance STOP input, provided that appropriate arrangements are made.
For this purpose, refer to the following the table:
Note 1.
Any number of NO devices can be connected to each other in parallel, with an 8.2K
Ω
termination resistance
Note 2.
The NO and NC combination can be obtained by placing the two contacts in parallel, and placing in series to the NC contact an 8.2K
Ω
resi-
stance (therefore, the combination of 3 devices is also possible: NO, NC and 8.2K
Ω
).
Note 3.
Any number of NC devices can be connected in series to each other and to an 8.2K
Ω
resistance.
Note 4.
Only one device with 8.2K
Ω
constant resistance output can be connected; multiple devices must be connected in cascade with a single
8.2K
Ω
termination resistance (see 11. What to do if…)
if the constant resistance STOP input is used to connect devices with safety functions, only the devices with 8.2K
Ω
constant resistance output (the resistance is inside the device) guarantee the fail-safe category 3.
1st device type:
NO
NC
8,2K
Ω
NO
In parallel
(note 1)
(note 2)
In parallel
NC
(note 1)
In series (note 3)
In series
8,2K
Ω
In parallel
In series
(note 4)
Table 1
2nd device
type:
NO
NC
8,2k
Ω
NOTE 2
NO
NO
8,2k
Ω
NOTE 1
NOTE 3
8,2k
Ω
NC
NC
!
