Controlled Products Systems Group HRG 220-A ST - Manual (Page 41)

Installation and Maintenance Manual
27
Connecting a Master / Slave Pair
The HRG 222 is automatically programmed to operate as a master slave set. If you are installing
two HRG 220’s to operate as a Master/Slave pair, the process is very simple. There is no need to
order a special model or any adapters. The area of the board marked Dual Gate employs a 3-wire
RS485 serial port for communication between Master and Slave operators.
1. An electrical conduit for the interconnecting wires must span between the two operators.
2. Complete the installation of both of the HRG 220 operators as separate machines and verify that
their basic functions are correct as solo operators before interconnecting them.
3. The two gate operators should be supplied by home runs from separate 20 Ampere circuit
breakers in the main panel, but if there is only one circuit, be absolutely certain that the breaker
and wire size is sufficient for the load of two motors. See Appendix 9.
4. External control inputs, vehicle detectors and entrapment protection sensors may be connected
to either gate operator without regard to preference.
5. To interconnect the two operators, route a shielded twisted pair with an internal ground wire
between the electric control boxes and connect to the RS485 Dual Gate terminals, in matching
order on both machines: In the RS 485 shaded area connect the terminals for Master Com to
Slave Com, Master A to Slave A and the Master B to Slave B using the insulated trio of wires.
Connect the shield to a solid ground at either the Master or the Slave unit (Do not ground both
ends). Cut off the shield and insulate (tape up) the exposed strands at the other operator.
6. The Installer Menu in each machine must be set as a Master or a Slave under menu item [dg__].
Set one operator as a Slave [dg_1] and the other as a Master [dg_2]. If the function of any
external input is to be different than the factory default, configure for the desired function on the
operator where that input is connected. Internal functions, such as the close timer or reversal
distance, are controlled by the Master operator regardless of the settings in the Slave.
7. Once set as a Master or a Slave the operators will be in constant communication with each other.
If that communication stops because the wires become severed or one operator is turned off,
both machines will cease functioning and the LCD will display Err4, which is a Master/Slave
communication error. This error cannot be reset until both machines are functional and
communicating properly again.