PR821-CH User Manual.doc
2018-04-05
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guarantees proper communication in a distance of up to 1200 meters as well as high resistance to
interferences.
3.6 Communication of controller with peripheral devices
The communication of controller and peripheral devices can be established by means of RACS
CLK/DTA. RACS CLK/DTA is the addressable bidirectional communication standard developed by
Roger company. Addresses of all devices connected to CLK and DTA lines must be properly
configured in range of 0..15. Factory default address of peripheral devices can be changed
according to procedures specified in their manuals but in majority of cases it is not necessary to
modify the addresses at all. Standard unshielded signal cables (e.g. U/UTP cat. 5) with maximal
length of 150m can be used for RACS CLK/DTA communication. Practically, devices communicating
on RACS CLK/DTA bus can be connected to the controller in distance up to 500m, but such
conditions are not guaranteed by the manufacturer.
The PR821-CH controller is equipped with built-in reader and can operate with external HRT82MF
reader, XM-2 I/O expander and HRT82FK function key panel. The address of external reader must
be ID=0 (default address is ID=1), the address of XM-2 expander must be ID=5 and the address of
HRT82FK must be ID=12. All mentioned devices must be connected to CLK and DTA lines of the
controller.
3.7 Input and output lines
Functions are assigned to input and outputs by means of PR Master software. The list of available
functions is given in the sections 6.1 Input functions and 6.2 Output functions.
3.7.1 Inputs
All inputs (IN1..IN3) of controllers have identical electric structure and can be configured as NO or
NC lines using PR Master software. The NO input is triggered by shorting it to supply minus (GND)
while the NC input must be normally shorted to supply minus (GND) and it becomes triggered when
connection with GND is interrupted. Every input is internally connected (pulled up) to the power
supply plus (+12V) through a 15kΩ resistor.
3.7.2 Relay outputs
Controllers offer one relay output (REL1) with single switching contact. Maximum load for REL1
equals to 30V/1.5A. In the normal state (relay is off) the NC-COM contacts are shorted. In the
triggering state (relay is on) the NO-COM contacts are shorted. In case of power outage both relays
remain in the off state.
3.7.3 General purpose outputs
Controllers offer two transistor outputs (IO1, IO2). Both outputs are open collector type i.e. in
normal (off) state are pulled to supply plus via 15kΩ resistor and when in trigger (on) state they
short to supply minus. Maximum load for each output equals to 15VDC/1A. In case of overcurrent
outputs are automatically switched off and controller automatically restarts.
3.8 Controller enclosure disassembly
Front part of controller enclosure is attached to the back part by means of latches. In order to
disassemble the enclosure it is the best to use included plastic key. If the key is not available then
flat screwdriver with 3-4mm tip can be used instead. Disassemble by inserting the key into each of
four holes in controller enclosure and push until each latch is released.
