Regarding the issue of signals from pneumatic control valves to the DCS

This explanation is correct. When an intelligent valve position controller is used with a pneumatic control valve, the valve position signal is automatically compared with the valve position command; if there is a discrepancy, the intelligent valve position controller reports the fault to the DCS system via the HART protocol. Therefore, there is no need to collect the valve position feedback signal. Furthermore, most modern DCS systems can support the HART communication protocol. Therefore, the AO modules of DCS can usually also receive HART protocol communications. In this way, signal interaction and fault reporting with the intelligent valve position controller can be achieved. .

This explanation is correct in some cases, but may not apply in others. Here are some more detailed explanations: The intelligent valve position controller automatically compares the valve position signal with the valve position command; if there is a discrepancy, it reports a fault to the DCS via the HART protocol, which is correct. This function is usually referred to as valve position tracking or valve position self-calibration. It allows the valve position controller to automatically adjust its internal counter in order to match the actual valve position command. If the valve position does not match the command, the valve position controller can send a fault signal to the DCS via the HART protocol. The AO module of a DCS generally cannot receive HART protocol communication. The AO module of a DCS can usually only send analog signals to simulate the valve position feedback signal. Therefore, even when a smart valve position controller is used, it is still necessary to connect a device that can convert the HART protocol between the valve position controller and the DCS, in order to send fault signals to the DCS. In summary, although an intelligent valve position controller can automatically compare the valve position signal with the valve position command, it is still necessary to collect the valve position feedback signal and send it to the DCS. At the same time, to receive HART protocol communication, a device capable of converting the HART protocol is required.

It’s not about considering the issue of the AO module receiving valve position signals; rather, it’s about whether your company has an intelligent device management system such as AMS. Devices that use standard industrial communication signals like HART are centralized in AMS, where many tasks can be carried out – provided that these intelligent devices, including various cards, comply with these communication standards.

The key is to see if the valve positioner of your control valve has HART functionality

Some positioners can accept AI signals; if not, the AMS system can be used to check the valve position. However, there may sometimes be a delay.