Up grading Analog input/output

[Will Steed]

I have to say, I love the product.  My only question is if there are any plans to go from 8 bit analog output to 10 or 12 bit on the M series in the future, same goes for the 10 bit analog input?  I know the software is not the limiting factor because you have to convert everything, so are there plans to upgrade the hardware?  
I can see a real advantage for 10 or 12 bit on the output especially.  I work with interfacing hydraulics to plc's and know that you can get good resolution on the modern proportional valves when working with motion control systems.  Most valves now have there own integral amplifer circuit attached, so you just have to input a command signal of +/- 10Vdc.  If you are limited to only 256 steps and have to convert to a bi-polar voltage, then you only have 128 steps for 0 to 10Vdc and 128 steps for 0 to -10Vdc.  (Most major manufacturers of Proportional valves make cheap modules to convert unipolar to bipolar voltages for directional proportional valves).

Just wondering because it seems the logical progression for an excellent product.

Will Steed

[support]

Thank you very much for the nice comments. Yes, it is always a "wish list" to go to 12-bit for both ADC and DAC. However, again it is a question of a balancing act between economics and capability. We want to maintain the product at very low cost for our OEM customers. Adding ?expensive 12-bit ADC/DAC on standard product where customers may or may not use them is not a viable option. We believe using the communication capability of the M-series PLC to access external ADC/DAC board is the best way of getting the higher analog resolution needed.

For ADC, there are a number of RS485 based, 12 to 16-bit "data acquisition" products on the market, with a wide range of possible interface including thermocoupler inputs. ?E.g:

 http://www.icpdas.com/products/7000/7000_index.htm
 http://www.rs-485.com
 http://www.dghcorp.com

There are fewer RS485 based DAC but DGH-corp and ICPDAS both have such products. Although we have not yet tested them directly we may be doing so with certain model(s) in the near future. These are usually based on simple ASCII commands and we believe it is not too difficult to program the M-series PLC to interface to such products.

[support]

We have just talked to the ICP-DAS people and we are getting a RS485 ADC and an DAC unit for testing. We will write an application note and sample .PC5 programs that works with the ICP-DAS product once we get the product tested. Stay tune.

[support]

We did it!

As mentioned in the previous post, we had obtained two units of the I-7000 modules from ICP-DAS. One of them is a 16-bit, 8 channel analog input module, ?and the other is a 2 channel, 12-bit analog output module that support 0-10V, 0-20mA or 4-20mA. Both modules proved to work readily with the M-series PLC via its RS485 port. We have written an application note and some sample .PC5 programs for working with these modules which can be found at the following link:

http://www.tri-plc.com/trilogi/I-7000.zip

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Multiple units of I-7000 can be multi-dropped from a T100MD+ or MX+ PLC, allowing hundreds of analog I/Os to be connected to a single PLC. Since the PLC can also be a MODBUS slave this can also serve as an ultra low cost RTU subsystem.

ICP-DAS also have other modules that may be of interest to M-series PLC users. These include one that connect up to 8 channel of thermocouple input directly. That means no need for expensive signal conditioners! Just plug the J,K or other types of thermocouple to the module's inputs, connect up to the PLC's RS485 port and instantly the PLC will be monitoring up to 8 temperature zones.

You can now purchase the I-7017, I-7018, I-7022 and I-7024 directly from us.