[123CNC]

From Mesa's product description,
'The 7I37 provides 8 Isolated 48VDC 1A output drivers. All output drivers are low saturation voltage...'

The boards look like they only recieve 5v from your PC via the 5i20 50 pin ribbon (unless optionally configured for 5v external at board).

How do they end up with 48Vdc output? Or does this signify the capacity, 0-48V input (similar to load on a traditional mechanical relay)? Sorry, not that familiar with MOSFET outputs, everything but. What is the proper way to use these, wiring to the + and - terminal of the output? positive power in at negative terminal and controlled output from + terminal to field device?

Thanks in advance

[PCW_MESA]

The 48VDC is an output rating, The 7I37 does not supply power, it only switches externally supplied power. Basically each 7I37 output is a isolated DC switch with a maximum switching capability of 1 Amp at 48VDC.

For example, If you had a 24VDC relay, normally you would wire the positive relay coil terminal to a +24VDC power source, wire the negative coil terminal to the + 7I37 output and connect the - 7I37 output to your power sources Negative or common terminal.

Since each of the output switches of the 7I37 are isolated, other connections are possible, For example its possible to drive ground referred loads (one side of load is grounded) by connecting the 7I37's + output to the positive power source and connecting the 7I37's - output to the load

Peter Wallace

[MrWild]

Excellent. This is the type of information that'd make your manual a little better. Your manual says it puts out 48v 1A but I too was confused how that came about.

The board "runs" on 5v, but it can handle up to 48v 1a switching loads.

[123CNC]

Much much thanks Peter.

Beyond explanation with a most likely example. THANKS.

I have the terminal version board, 7i37t. The board's terminal markings differ from the manual. I trust the board art is correct. There is also slightly different markings than what appears in the manual. Most will figure it out, but some may be a little confused before they do, and some will remain confused.

Thanks again, and might have to get another I/O board. Trying to best utilize the 8 outputs without expanding.