Description
SnipCard Dual Relay with INTERLOCK option
This powerful SnipCard mounts onboard two mini relays to be used with max 36 V and 2 A devices. It’s very useful when employed as servo-relay actuator, but it’s also very handy for every “clean contact” (SPST) application. On Archiduino Base Board you can mount up to 10 Dual Relay SnipCards.
Details
The Dual Relay SnipCard has been engineered in order to be flexible and sturdy. It mounts an inverting triple Schmitt trigger IC performed by a NXP’s 74LVC3G14. The coil activation is done with two reliable BC847 NPN transistors. There are two LEDs, one for each relay, to show the relay’s status.
The SnipCard works in interlocking mode: relays are working in master/slave mode. If relay A (master) in ON, relay B is deactivated (forcedly set to OFF). Relay A has always priority on relay B.
Examples of use
Example 1: relay A activates a cooling fan with the purpose of decrease the temperature of a heating element activated with relay B. We need to be sure that heater B is OFF in order to cooling it down efficiently without energy waste.
Example 2: we need to drive an open/close motorized valve that hasn’t any system to avoid activating both open and close actions at same time (it happens, trust us). Setting priority to close, the potentially damaging action on both operating directions will be safely avoided.
Example 3: we have a simple DC motor to be driven with plus or minus voltage in order to set rotation sense. What happens if we wrongly activate both polarities at same time? Yes, you know. In the best case we replace a fuse, in the worst one we can assist to artistic smoke puffs. Interlocking mode actually avoid situations like this.
Test Video
Package contents
n. 1 SnipCard with INTERLOCKED configuration (with no delay options).
Attachments
NXP 74LVC3G14 – Triple inverting Schmitt trigger – datasheet
NXP BC847 NPN Transistor – Datasheet
Examples
void setup() { pinMode(M7A, OUTPUT); pinMode(M7B, OUTPUT); } void loop() { delay(1000); digitalWrite(M7A, LOW); // set "ON" relay on channel A delay(1000); digitalWrite(M7A, HIGH); // set "OFF" relay on channel A delay(1000); digitalWrite(M7B, LOW); // set "ON" relay on channel B delay(1000); digitalWrite(M7B, HIGH); // set "OFF" relay on channel B }
Examples of code and description