Two sets of DCS are connected via hardwired communication; seeking guidance on the method.
Thread Content
Our factory originally had one set of DCS; now a new DCS has been installed in the new workshop, and it is required to communicate with the old DCS via hardwired connections. The card modules are connected directly using multi-core cables; digital signals can be converted to dry contact nodes by using relays. How are analog signals converted? Is it possible to use a combination of four-wire and two-wire cards, for example, with A outputting 4-20mA to B? In that case, A would need to be connected to an AO card, while B would need to be connected to a four-wire AI card? Should I still use a signal isolator to connect to the two-wire AI card?
This post was last edited by huio1983 on 2017-8-21 at 14:44. Why a hard connection? Can’t we set up a control station and use remote communication instead? The key point lies in the hard connection – is it for expanding the production process? Analog signals are tapped using a 1-input 2-output signal isolator; relying solely on the AO output would require too much investment (of course, if you have the money, you can do as you wish)
If the two systems share the same grounding system and the potential remains constant, then an isolator is not necessary; the AO signal can be directly sent to the four-wire AI card
A small amount can be replaced with a 1-to-2 converter, but the cost is not low.
Why is the investment so high just for AO output? Isn’t it just taking up channel and cable budgets? Hardwiring is used because only a few signals need to be communicated between the two DCS systems.
What is a 1-to-2 converter? What’s its technical name? Is it dividing something into two? Is this thing expensive?
A few signals are okay; I understand that all AO outputs should be connected
Signal isolation distributor; foreign-brand models cost over 1,000, with one input and two outputs