Laseshark Connections

[troglodisme]

I have recently received my LaserShark board and a set of Galvo from ebay (http://goo.gl/OtRkrr) and struggled to understand how to connect them as the Galvos came with barely any information.

Jeffrey was really helpful via email and asked me to post the question here for future similar problems. This is his sketch of the connections between the galvo amplifier and the lasershark

I am still not quite sure about the rest of the connections, but I guess they go directly to the laser (which I haven't received yet). If anyone has a complete set and wants to post a picture/diagram that would be awesome..

[Macpod]

Just a FYI for others who are reading this:
Generally galvo kits purchased off eBay and other sources will have one of three data header configurations:

1. Galvo amplifiers with 2-pin data headers:
Galvo amplifiers with this type of connection are low cost, low quality, and have low point-per-second (PPS) ratings. They also do not use differential comms so they are prone to noise issues.

The data header pins on these galvo amplifiers correspond to GND and +Channel.

To use this type of galvo system with a LaserShark

• Connect the GND pin of the galvo amplifier data header to the GND pin of the respective X/Y header on the LaserShark
• Connect the +Channel pin of the galvo amplifier data header to the +Channel pin of the respective X/Y header on the LaserShark
• The respective X/Y -Channel pin should remain unconnected!

2. Galvo amplifiers with 3-pin data headers:
This style of galvo amplifier data connector galvo kits seem to be the most common. Normally they ship with a data cable that can be plugged directly into the LaserShark without need to re-arrange the pins in the header but this cannot be guaranteed to always be the case.

The data header pins on these salvo amplifiers correspond to GND, +Channel, and -Channel. It is possible the order of these pins will vary thus it is important to review the data sheet accompanying these galvo amplifiers before using them as well as the silkscreen on the galvo amplifier PCB. 

To use this type of galvo system with a LaserShark

• Connect the GND pin of the galvo amplifier data header to the GND pin of the respective X/Y header on the LaserShark
• Connect the +Channel pin of the galvo amplifier data header to the +Channel pin of the respective X/Y header on the LaserShark
• Connect the -Channel pin of the galvo amplifier data header to the -Channel pin of the respective X/Y header on the LaserShark

3. Galvo amplifiers with 4-pin data headers:
These are sometimes seen with higher PPS rated galvo amplifiers. and have the same pins as the 3-pin data headers but with an extra GND pin.

[Macpod]

As you have probably noticed already, there is more than one three-pin header present on your galvo amplifier boards.

The one with +24, GND, and -24 silkscreened next to it is the input power header used to power the galvo amplifier. +/-24V are pretty common markings but not ubiquitous to all galvo amplifier models. The LaserShark should NEVER be connected to this header.

The other header with the silkscreen markings +15, GND, and -15 is used to provide power to the analog section of some laser showcards. The LaserShark is not amongs these and should NEVER be connected to this header either.

[Macpod]

If you have not seen it yet, this page explains all the headers on the LaserShark:
http://macpod.net/electronics/lasershark/lasershark_usage_electrical.php

[troglodisme]

Hi there,

Thanks for the explanations. I have finally received the laser as well, and more doubts came up. I am pretty determined to get this going, so once it's all setup I can make a tutorial for dummies (like me) using the lasershark as the main board.

So this is the board that came with my laser, one cable goes to the power supply and other two go to the laser unit. I assume I need to connect Channel A of the lasershark to "CN1" of the laser pcb but I wanted to double check first

THanks!

[Macpod]

What is important to keep in mind when connecting lasers to the lasershark are that there are two analog channels (A and B), and one TTL channel (C).

TTL means the output can be turned on or off only.
Analog means the output can be turned off, turned on 10%, 20%, etc.

The LaserShark is NOT a power source for lasers. You will need to power the LaserShark using an appropriate power supply. The LaserShark is intended to provide a signal to control a laser module only.

Markings on laser module inputs vary wildly so without additional information I cannot say if the CN1 input is actually the input or not. Do you have a manual for this module or an image of the inputs and labeling?

[troglodisme]

Hi there,

I have attached the image to the post, did it not come up? Regarding the power: the laser came with its own power supply so that shouldn't be a problem.

You can find it here: http://s8.postimg.org/kml78pywk/Screen_Shot_2015_04_19_at_10_42_32.jpg

[Macpod]

Thank you. The original link did not appear. It is possible that particular website does not allow off-site linking. This forum has an ability to upload images to the boards by the way. They format a little better than off-site links too (for now.. I'm going to have to fix that IMG tag!).

As for this driver, it looks like one of the super-common and low cost O&E dual TTL signal controlled diode drivers. Normally the pcb is potted on these but I guess they left this off to make this driver as cheap as possible.
It also looks like they didn't include a Peltier for diode temperature regulation with this module assembly. CN1 is the header which normally connects to this. DO NOT CONNECT CN1 TO THE LASERSHARK!

If you look on the back of the plastic cover there should be markings indicating what connector does what.
You will want to connect the "GREEN-LASER Blank+" pin to one of the LaserShark's laser +channel lines. Next you will need to connect the "GREEN-LASER Blank-" pin to the respective LaserShark laser channel's GND pin.

The "GREEN-LASER signal header in your image has been marked "+GT-".


Which channel (A, B, C) doesn't matter. The analog channels (A and B) are just as capable of controlling TTL signal controlled laser drivers as channel c (the TTL-only laser channel on the LaserShark).