Mesa card selection for machine with resolvers - resolver questions

HI there
I have started a new retrofit of a Mitsui Seiki HR5 machining centre of 1981 vintage.

The machine is equipped with resolvers (1st time for me). below is a photo of the X axis resolver and a photo of the wiring diagram showing the connections, photo of the Inductosyn scale, fanuc pre-amplifier.

Questions:

The wiring diagram clearly show two excitation signals (sin,cos), but the most resolver interfaces i found online only provide one excitation signal?

The easiest for me would be to use the Mesa 7i49 to get the position feedback into LCNC, but im not sure about the two excitation signals? any advice would be appreciated. I could not find any info on the Fanuc pre-amp, would this be required with the 7i49?

For the full system, im planning to use a 7I80HD + 7i49 + 7i44 +7i70 (x2) + 7i71, i still have a problem with the spindle encoder which will have to be added, but this string of mesa cards done have encoder input interfaces, should i just look for a rotary resolver for the spindle online? Comments on this would be great

Thanks in advance

Resolvers can be run either way. You can send a single signal to the "rotor" and recieve two signals of varying amplitude on the "stator" windings. Or, you can drive two out-of phase signals to the "stator" windings, and observe the time of the zero crossing on the "rotor".

The resolver rotor is equivalent to the Inductosyn spar. And, the resolver stator windings are equivalent to the two windings on the Inductosyn slider.

Jon

Unfortunately the 7I49 will not work with inductosyn scales 1. Because of the 2 phase
excitation requirements and 2. Because of the very low impedance, high frequency
excitation and low level output signal.

I think the 2 phase excitation was used on older devices because the interpolation
can be done without analog processing, basically by just measuring the phase
difference of the excitation and the scale signal (a simple digital counter measuring
time between zero crossings)

Maybe you can find an inductosyn/quadrature translator.

That is unfortunate...those converters from Vega cost $1250 per channel.

It might not be totally impossible to use s 7I49 if you wired the Inductosyn like a resolver
(excitation on the scale) and you had a gain of 50 to 200 preamp for the sine/cosine signals

Do you have access to an oscilloscope?

Hi PCW. Yes, I do.
Henk

Hello,

we use this type of inductisyn scales on retrofitted machining center with VEGA converters. But it is hard to setup the converters. Easier and better to install new incremental linear scales. This inductosyn is technology from `60.-s.

Hi. I also replaced the linear scales but the two rotary axes required very high resolution and it was cheaper to keep the rotary inductosyn encoders.

I purchased Farrand control converters on eBay and manages to set them up using the original pre-amps.

I am very happy with the result.

Henk

Hi Henk, are you from RSA - I am from Port Elizabeth and am trying for many years to find a solution for my home cnc machine which has old resolvers on it - I want to go LinuxCnc type retro but want to use the old stuff - it's a home hobby not a production machine so I am looking to save where I can - you mention Farrand control converters (is this able to convert analogue to digital signal on resolvers etcetc)
I would appreciate any input + I am aware of SA CnC club but it's in JHB and too far for me to attend lectures