Sending TTL to Coulbourn/Windaq Setup

Greetings-
We're using Coulbourn physio equipment and have just upgraded to Windaq
physio acquisition software. In the past, we've been using some kind of
homemade circuit box to transmit a TTL signal from the parallel port of the
computer running MediaLab to the Coulbourn port (V19-16). Now we've got a new Coulbourn port (V19-02) and a DataQ DI720 USB acquisition system
especially for Windaq.

Here's my question-I'd like to make a new, more robust connection that will
allow us to send TTL signals from MediaLab to the new port. The homemade
box that we've been using is falling apart, the grad student that made it is
no longer around and none of us know how to build such a device. I thought
maybe someone here would know how this is done and could offer some advice. I've looked around on the web and haven't been able to find much.
Alternatively, if you know of anyone using a similar setup and
are comfortable connecting me with them, I can go that route.
Thanks a million.

I'm not too familiar with the Coulbourn equipment.

Is there an input somewhere in the system which can be configured as a 'trigger' somehow?

If there is, it's a simply matter to build an adapter cable to connect your MediaLab computer with the Coulbourn system. We'd be happy to give you a wiring diagram and assembly instructions.

John

Thanks for your reply. There are two possibilities for inputs.
1. Our existing setup (the homemade one that I'd like to modify) runs from the printer port of the MediaLab computer to a circuit box of some kind. There are 4 outputs from the circuit box that are plugged into digital inputs on the back of the Coulbourn port (V19-02). With our old software, the Coulbourn port was connected to our old physio data collection computer via a parallel port cable.

2. With our new system, the Coulbourn port is connected to a DataQ DI-720 Data Acquisition Module for WinDAQ Pro software, which then connects to our new physio data collection computer via USB. The connection from the Coulbourn port is made with a 37-pin D connector. There are two possible 37-pin connection inputs, one on the left side and one on the right side of the DI-720. This is straight from the DI-720 Manual:

DI 720 Series instruments can accept 32 high-level or preconditioned analog inputs in single-ended configuration or 16 high-level or preconditioned analog inputs in a differential configuration. High-level inputs are typically low impedance, no-conditioning required signals in the range of +/- 1.25 to +/- 10 volts full scale. Single-ended inputs are configured by connecting one signal lead to the desired channel and the other signal lead to analog ground (AGD).

(Me again). There are two channels (pins) on the right side input of the DI 720, R.Start/Stop and Evnt, which looks like they are designated for remote event triggers.

So to answer your question, it looks like there are two input options-one on the Coulbourn port and one on the DI-720. One question I have is whether it makes more sense to send the TTL from MediaLab to the Coulbourn port or to the DI-720. I realize this is a question for the Coulbourn/DataQ people, I'm still waiting on a reply from them. If what I've said makes enough sense that you can send assembly/wiring instructions, that would be great.

Thanks so much for your prompt assistance.

It's probably not important which piece of hardware you connect the MediaLab computer to. If it were me, I'd start with the 'event' input you've mentioned below.

It's a fairly simple matter to make a new cable to connect the two systems.

You'll need two wires: one which connects MediaLab's 'D0' pin to the 'event' input on your hardware, and one which connects ground between the two systems.

Take a look at this forum posting:

[url]http://www.empirisoft.com/support/showthread.php?t=762[/url]

The idea is the same. However, instead of connecting to 'nACK' on the second machine, you'll want to connect to the event input of your outboard hardware.

It's probably a two minute job with a soldering iron and multimeter, if you have those things available.

Does that help?

John

Thanks, John. This is helpful. Another question: Is it possible to set up more than one TTL connection? The input that the TTL will be sent to can take two different pulses-one to start/stop data collection and one to trigger an event marker in the data. This requires 4 total connections-the two TTL connections and an analog ground for each. The thread you posted mentioned 2 connections (1 TTL/1 ground), I'm wondering if I can do more.

Finally, what type of wires/connectors are needed to make this connection?
Again, I appreciate all of your help.

[QUOTE] Is it possible to set up more than one TTL connection? The input that the TTL will be sent to can take two different pulses-one to start/stop data collection and one to trigger an event marker in the data. This requires 4 total connections-the two TTL connections and an analog ground for each. The thread you posted mentioned 2 connections (1 TTL/1 ground), I'm wondering if I can do more.[/QUOTE]

No problem at all. I'd use the data bits 0 and 1 in your parallel port. This would be pins 2 and 3 on your parallel port. You could use pins 18 and 19 as ground connections as well.

Addressing these separate pins is a matter of sending out the proper byte to the port:
Bit # 7-6-5-4-3-2-1-0
----- X-X-X-X-X-X-X-X <= port is 8 bits wide

Sending decimal value '1' will activate bit 0. Sending decimal value '2' will activate bit 1. Sending '3' will activate both.

[QUOTE]Finally, what type of wires/connectors are needed to make this connection?
[/QUOTE]

You'll probably just need a DB-25 connector of the proper gender (remember, males have pins and females have sockets) to match your computer. Then I'd just use some basic 20-22 gauge hookup wire to make the connections.

If the answer is yes, I'm the one that built the old interface between MediaLab and the Coulburn unit. Let me know what problems you have and maybe I can help somehow.
I also have TTL connection problems on different equipment, so I understand the frustration.