Recent content by automation99

Can anyone help me to understand bias control, is this same as ratio control to have proportional control of two related control variables? Thanks.

Thanks, Irob.If I am not mistaken, using DeviceNet means treat the AB compactLogix as remote I/O, all logic will be done in GE PLC. That is not what I want, AB compactLogix is come with its logic and programm from vendor. GE will be the upper level supervision and only shutdown function from it...

Thanks, JMW. One of the configuration I've seen is to use larger impluse line bring in more samples and branch out smaller tube to the analyzer and the rest return to the lower pressure process line. I think this can avoid any dead leg or sample lag.

In analyzer sampling system, fast-loop has been used very often, what does it mean by definition? Is there fixed configuration of fast-loop?

Thanks, JesperMP. I do need real time and precise control between these two PLCs, the AB compactlogix is BMS which contains important information. Isn't DeviceNet AB's proprietary network? Can GE support it? I believe GE support Modbus, but that will be even more complicated to involve third...

Thansk, Chris. If I use common OPC server, do I get real time response from one to another? Is there time delay? There are about 20 discrete signals and 5 analogs. Does AB and GE both support Modbus?

I have one AB compactLogix PLC and one GE 90-30 PLC (client prefered), if I choose DH+ to communicate between these two, do I need to have any converter for the GE PLC or just plug these two and they can talk to each other? I am new in this field, please help. Or should I insist to have AB...

SIL - Safety Integrity Level

AB ControlLogix 1756 is rated for SIL 2, does it mean I will get SIL 2 in any kind of configuation, or I have to be careful select components of controlLogix to make it SIL 2, such as redundant CPU, redundant network? To what level of redundancy I need to make it SIL 2? Thanks in advance.