Mesa 5i25+7i77 plug-n-go configuration

Regarding field inputs, I am working the home circuit, currently I have 15 amps, and I am going to use a resistor to take that down to one amp for the 7i77. I don't see a max amperage for inputs, what value is other builders using safely with the 7i77?

The 7I77 field inputs sense +DC voltage and expect that the input will come
from the field power source (Usually 12 or 24VDC )

so for a home switch the normal wiring would be:

+24VDC field power --> SWITCH --> 7I77 INPUT

The input resistance is 22K Ohms and the input threshold is set to about 1/2
the field voltage

Just a quick logic check.

I set up the circuit to give:
>14.4v nominal
<9.6v when the home switch is deployed

Is that correct or do I have it backwards?

Those thresholds are correct for 24V field power
but as I said before, switch wiring would normally be:

+24 VDC field power --> SWITCH --> 7I77 INPUT

No need to make it more complicated than this.

For limit switches, Normally Closed (NC) is preferred
so you would use the hm2_5i25.0.7i77.0.0.input-xx-not pins
that will be "true" when a NC limit switch is depressed.

Your question about home power scares me a little,
no 120V power should be anywhere near the
control electronics (the Field IO is 10 to 32V DC only)

My apoligies, I will clarify.

I am using 24volt field power, as described in the line below.

+24 vdc field power -->switch ---->7i77 input

I did not realize we could change the Hal file to reverse the logic, with "not" command added at the end of input definition

For limit then;
1) Hal file input is defined with "not"
2) when input senses nothing or ground = true
Wire switch to normally be field power , and to zero when limit deployed


Thank you for your patience

The "not" in the name is not a hal command but rather the signal ending in -not is a separate signal

Many hal input signals are provided in both polarities as a convenience

2) when input senses nothing or ground = true
Wire switch to normally be field power , and to zero when limit deployed

Yep

Hello,

I am getting some errors at startup, curious if anyone might be able to point me in the correct direction. The error code has good information I do not have the expertise currently to decipher.
I am at the early stages and trying to setup just one axis, could this be a problem in my hal file, or does it sound more like hardware?

I am using the 5v from 5i25
I have 24v field power

(error 1)
hm2/hm2_5i25.0: Smart Serial Error: port 0 channel 0. You may see this error if the FPGA card read thread is not running. This error message will not repeat.

(error 2)
hm2/hm2_5i25.0: Smart serial card 7i77.0.0 error = (13) Communication error

(error 3)
hm2/hm2_5i25.0: Smart serial card 7i77.0.0 error = (3) Timeout


problem resolved:
After using a new cable from the 7i77 to 5i25 these errors ceased. 12/1/2014

This suggests a power supply issue of some kind since it looks like communication to the field I/O section
of the 7I77 was lost at startup

I would verify that the 7i77 logic 5V supply is correct (4.5V minimum 5.5V maximum)
The check that the field I/O power is OK (8V minimum 32V maximum <0.5V ripple)

a shorted output and a weak field supply might cause this error also