Compact replacement for SLC500

[micgent]

I wish to replace an SLC 500 which uses an 1746-N04V Analogue o/p card. As I understand these cards are 14bit D-A.

I looking for recommendations for a replacement Compact Programmable relay type PLC where the add on D-A cards are of same or greater resolution?

What i dont understand is when I look at the existing program/Data File/N11:0 There is a decimal figure in there of "18000" which is Binary "0100011001010000" 15 bits are being used here?

 

[Mickey]

Where does N11:0 get its data from? Post your code if you can.
For a voltage output it looks normal to me. About 5.5 volts output at that count
value ( if N11:0 is written to the output word)

 

[micgent]

Whats the best format for posting the code? please

 

[Mickey]

Whats the best format for posting the code? please

Zip your .rss file then post. ( may not be necessary if the PDF answers you question about the 14 bit spec).

See PDF ( top paragraph) below for an explanation on the 14 bit spec.

 

[micgent]

file:///G:/Neutronics/NeuWorkshop/Projects/Torque Tool/E011702a.zip

Hope this works

 

[micgent]

 

[micgent]

Ok I think ive uploaded the zip file.

 

[micgent]

The analogue o/p is 0-10v and is driving a Pneumatic Valve of 0.8% sensitivity. So by my calculation 8 Bit resolution GIVES: 10volt divided by 255 gives 39.21mV resolution. 0.8% of 10volt is 80mVolt, so 8 bit should cover my needs.

Now that ive posted the code I would love an explanation as to what is going on.
The code is used to control a torque wrench with 4 preset torque settings.

 

[micgent]

Having now read the PDF re 14Bit

Thank you for the pdf.
Having now read the PDF re 14Bit, I understand why I was confused the 2 LSB are not counted. It did cross my mind if unused bits were used for polarity. I will have to read the manual to find out the full spec on the o/p.

 

[TConnolly]

Left justifying the 14 bit A/D conversion in a 16 bit number allows compatibility between modules/platforms. eg, the same program instruction, SCP I:1.0 0 32767 0 100 still scales correctly whether you are using a 14 bit A/D or a 16 bit A/D - thus if you replace a SLC500 with a Micrologix then thats one less part of the program you have to change.

If you are looking for a micro replacement and you want to minimize re-writing the program and you have only a few analog points then you might want to consider using a Micrologix 1100 or 1400 - the 1100 has two 10-bit analog inputs built in to the base unit, the 1400 has 4 analog inputs and two analog outputs built in. Aside from IO addressing your SLC500 program should be about 99% compatible. Just open the program and change the processor type and then correct the addresses, change any OSR to ONS, and viola, programming done.

 

[micgent]

That sounds like a good idea thanks Alaric.
Mickey thanks also

 

[fryman]

routeco still have a few mx1400 in stock, so if you are quick you can get your hands on one before the shortage comes to eu.