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How to use a dry contact to wirelessly trigger the flash LED alarm horn?

In general, RF wireless control systems use a remote control or a transmitter to control the device that connected to a wireless receiver. However, in some special applications, we need to use of a dry contact (normally open / normally closed contact) to remotely trigger or control another device in the distance.

One of our clients owns a shop. In the daily operation, it is necessary to maintain public safety, so he installed a security alarm system in his shop, equipped with wireless magnetic detectors, wireless infrared detectors and wireless fire detector. When these detectors are triggered, the warning horn that connects to the warning system will sound the alarm at the same time. After the shop is closed in the evening, he usually will go home and enjoy the rest time. The shop is about 800 meters away from his home. In case there is any unexpected situation in the shop, such as breaking into a thief or a fire alarm, the warning horn in the shop will be triggered. But because the shop was too far from his home, he could not hear the alarm sound, which would delay the best time to take remedial action. So, the client contacted us, also told us about his worry. He wanted us to figure out a wireless solution to install a wireless system. The reason is that he paved a line from the shop to the home is not realistic, and he would like to install an warning horn at home, when the shop warning host is triggered, the home warning horn will ring simultaneously. He told us that his alarm host had a normally open contact output. When the alarm host was triggered, the normally open contact output would be closed.

We recommend a normally open contact wireless trigger alarm system (model 0050001) based on the client’s situation. The system includes a transmitter CB-2N (model 0021045), a wireless receiver S1X-DC12-ANT3 (model 0020490), a flashing LED Alarm Siren (model 0040027) and a DC 12V power adapter (model 0010124). The transmitter CB-2N is a normally open dry contact trigger type, which has two input lines, and the two lines are usually disconnected. When connecting these two lines, the transmitter is triggered and a radio control signal “ON” is transmitted. However, when these two lines are disconnected, the transmitter is also triggered and another radio control signal “OFF” is transmitted. The receiver S1X-DC12-ANT3 is a DC 12V input / output type with a maximum operating current of 10A and has a waterproof case and an external telescopic antenna that can be installed outdoors for use. When this receiver S1X-DC12-ANT3 is triggered, it will output DC 12V power. This flashing LED Alarm Siren works at 12V DC power supply. When it is connected to the DC 12V power adapter, it will sound an alarm and flash at the same time, and the volume of the warning sound is also adjustable. This normally open contact wireless trigger warning system in the open area can be achieved as far as 1000 meters working distance.

The example diagram and specific operation of wireless remote control warning system are as follows:

The client first connects the normally open contact of his alarm host to two input lines of the transmitter CB-2N, then connects the DC 12V power adapter to the wireless receiver S1X-DC12-ANT3, and connects the alarm light to the output of this receiver. When any detector in the shop is triggered, the alarm host is triggered and the normally open contact output are closed. The transmitter CB-2N is triggered simultaneously and transmits an “ON” wireless signal to the receiver in the far range. When the receiver S1X-DC12-ANT3 receives this wireless signal, it outputs a DC 12V power to turn on the flashing LED Alarm Siren. When the alarm host lift the alarm state, then the normally open contact output will be disconnected. The transmitter is triggered again and an “OFF” wireless signal is transmitted to the receiver in the distance. When the receiver S1X-DC12-ANT3 receives this wireless signal, it will stop outputting 12V power and the alarm light will be turned off at the same time.

This type of RF wireless control system consists of a transmitter and a receiver. Transmitter can be used to connect a variety of devices with normally open / closed contact output, such as warning host, cable detectors, various sensors, limit switches, PLC programmable controllers (Programmable Logic Controller) and so on. The receiver can be connected to a variety of DC / AC equipments, such as alarm speakers, lights, pumps, motors, electric doors and so on. Normally open contact wireless remote control kit mainly utilizes one device with normally open / normally closed contact output to wirelessly control another AC or DC device. It can be used in many industries such as reservoir level control, automatic remote control of industrial equipment, simultaneous remote control of agricultural equipment, and the like.

In the online shop Carymart, we have two types of transmitters, which are CB-2N (Model 0021045) and CB-2N-2 (Model 0021046). We have three types of receivers. 1. DC power output receiver, such as receivers S1X-DC12-ANT3 (model 0020490) and S1PX-DC12-ANT2 (model 0020438), they are commonly used to control DC equipment. 2. AC power output receivers, such as receivers S1X-AC220-ANT3 (Model 0020393) and S1PX-AC220-ANT2 (Model 0020442), they are commonly used to control AC equipment. 3. Relays (NO / NC) Output receivers, such as receivers S1U-DC12-ANT2 (Model 0020249), S1U-AC220-ANT3 (Model 0020466), S1PU-DC12-ANT3 (Model 0020302), and S1PU-AC220-ANT3 (Model 0020488). These relay type receivers act as a single-pole double-throw switch, and its relay output has three output terminals (normally closed, normally open, and common) that can be used to control various DC / AC equipments.

Transmitter CB-2N has two input lines; the working principle is as follows:

  1. When two input lines are connected, the transmitter automatically transmits an “ON” wireless signal, equivalent to the function of the button “ON” on the transmitter.
  2. When two input lines are disconnected, the transmitter automatically transmits an “OFF” wireless signal, equivalent to the function of the button “OFF” on the transmitter.
  3. When the receiver receives this “ON” or “OFF” wireless signal, it will drive its relay to turn on / off the connected device.

Transmitter CB-2N-2 has three input lines; the working principle is as follows:

  1. When the input lines 1 and 3 are connected, the transmitter automatically transmits an “ON” wireless signal, equivalent to the function of the button “ON” on the transmitter.
  2. When the input lines 2 and 3 are connected, the transmitter automatically transmits an “OFF” wireless signal, equivalent to the function of the button “OFF” on the transmitter.
  3. When the receiver receives this “ON” or “OFF” wireless signal, it will drive its relay to turn on / off the connected device.

Notice: The operating voltage of the transmitter is DC9V, and it can work for about 3 days with a model 6F22 9V battery. If the device has to work long term, we recommend using a DC9V power adapter.