Trying to learn and have a project in mind

[Josh W]

So pretty much I have very minimal prior knowledge of circuit building. I am somewhat experienced with soldering SMT and through hole. I want to learn to make my own circuits though, does anyone know any good books or books to get started? I have a project in mind and I will explain why.

I currently work at a 5 radio station cluster as the broadcast engineer with no education in the field. We have a piece of equipment called a sage digital endec which broadcast eas alerts. For those of you that do not know what was is, it is the emergency alert system .... The annoying alert you hear on the radio sometimes. Well I want to build a circuit where when contacts a and b are connected the the board will either flash and blink or make a somewhat loud and obnoxious sound. The tricky part is that I cannot create a current between contacts a and b. The reason I want to make this is because I can make one of the rs232 ports on the back of the endec connect those two contacts when there is a pending alert so the noise or the flashing light would alert our dj that the eas is coming.

Any suggestions/advice (preferably in laymans terms)?

 

[Pommie]

You need to explain your problem better. What is going where via RS232? What are contacts A and B? How does a port connect contacts?

Mike.

 

[alec_t]

Welcome to ETO!

I cannot create a current between contacts a and b

Why not? What are the contacts for?

 

[dr pepper]

Hello and welcome, I'd like to be a broadcast engineer too.

I dont get what you mean by rs232 either, are you saying you can force the module to create an alert using rs232.

When you say current, it sounds like you mean the alert generator has a low current rated contact.
The way to handle this maybe is to use an opto isolator to control the external circuit, in fact you might not need a lot else.
We do need a better explanation though.

 

[chemelec]

Do A & B go High or Low when connected?

 

[Reloadron]

Much of this will depend on the particular ENDEC unit that you are using in your system and how the ENDEC unit is configured. Here is an example of what I am getting at for a specific unit with all the I/O information covered. What you are looking to do does not seem complicated but will depend on exactly what you have and hoe it is configured. So what exactly do you have and how exactly is it currently configured?

Ron

 

[Josh W]

Much of this will depend on the particular ENDEC unit that you are using in your system and how the ENDEC unit is configured. Here is an example of what I am getting at for a specific unit with all the I/O information covered. What you are looking to do does not seem complicated but will depend on exactly what you have and hoe it is configured. So what exactly do you have and how exactly is it currently configured?

Ron

I am using the newer 3644 unit. And I was told by sage support that I can configure one of the com ports to create a pin closure for incoming alerts. When I said that I cannot send a current through the contacts I was more than anything trying to be safe rather than sorry because I would hate to fry the port or even worse fry the unit by tinkering beyond my level of expertise.

 

[Josh W]

Hello and welcome, I'd like to be a broadcast engineer too.

I dont get what you mean by rs232 either, are you saying you can force the module to create an alert using rs232.

When you say current, it sounds like you mean the alert generator has a low current rated contact.
The way to handle this maybe is to use an opto isolator to control the external circuit, in fact you might not need a lot else.
We do need a better explanation though.

For example the rs232 port on the back of the endec can be configured to create a pin closure between 2 of the pins for an incoming alert. Not exactly sure what pins yet but for now let's just say that pins 4 and 5 will connect when an incoming alert is pending. I would prefer to assume that the com ports on the endec can't handle hardly any current just to be safe.

 

[MaxHeadRoom78]

If it uses full hardware handshake protocol, DTE/DCE, you could possibly use the RTS signal and latch or otherwise detect it.
You most likely will need to condition it for operating a device.
Max.

 

[Reloadron]

I am using the newer 3644 unit. And I was told by sage support that I can configure one of the com ports to create a pin closure for incoming alerts. When I said that I cannot send a current through the contacts I was more than anything trying to be safe rather than sorry because I would hate to fry the port or even worse fry the unit by tinkering beyond my level of expertise.

Do you mean the new 3644? Then all you need to do is program the unit to do what you want using the HTTP programming interface. You should be able to use any of the six serial ports (DB9) or maybe even any of the four dry dry contact closures offered. I don't have a manual for what you have but the manual should cover this. Additionally the guys who market this may sell an optional relay card for use with any of the RS232 ports. The trick if we call it a trick is simply in the programming of the units IO to do things when alerts occur.
Data Interface
• Six serial ports, DB-9, for relay panel interface, hand held remote control, CG control, LED display, automation, etc.
• Two USB connectors, for printer, additional storage
• Five GP inputs for automation interface, trigger of RWT or forward of alerts on up to four stations
• Four dry contact closures for automation interface

Ron