For DCS drive motors, is it better to use single drive (ON for operation, OFF for stop), or dual drive (one pulse for operation, one pulse for stop)?

It is necessary to first analyze their respective advantages and disadvantages, and then choose which approach to use based on the specifics of the project. Single drive (ON for operation, OFF for shutdown): Advantage: It requires few points – only one DO point is needed to control the start and stop of the pump ； Electrical components take up less space, and the wiring is correspondingly simpler. The investment cost is low. Disadvantage: During pump operation, the coil of the intermediate relay must remain powered continuously; over time, the coil heats up, resulting in higher power consumption ； It will shorten the service life of the intermediate relay ； When the quantity reaches a certain scale, higher requirements are placed on the ventilation and heat dissipation of the distribution box. The failure rate is higher compared to dual drives. Dual drive (one start pulse, one stop pulse): Advantage: During the pump’s start and stop, the corresponding relay coil does not need to remain energized continuously. Lower power consumption, and a longer service life for the intermediate relay. There are no high requirements for ventilation and heat dissipation in the distribution box. The failure rate is lower compared to a single drive. Disadvantages: It requires a large number of points; 2 DO points are needed to control the start and stop of the pump ； Electrical components take up more space. The corresponding wiring is also more complicated, resulting in higher investment costs. Below is information found online regarding the impact of temperature on relays: Rising temperatures accelerate the aging of the relay’s insulation; as the insulating properties decline, the lifespan of the relay is reduced. For relays, an increase in temperature, along with the thermal deformation of certain insulating materials, causes changes in the product’s structural parameters and operating parameters ； An increase in coil temperature not only accelerates the aging of the paint coating, but also has a direct impact on the changes in the pickup and release parameters of the relay. Increased power consumption also affects insulation and contact switching characteristics ； Rising temperatures accelerate the oxidation process of certain components. For contacts, not only does the material itself oxidize, but it also accelerates the formation of surface film resistance, which directly affects contact reliability, especially at low voltages ； As the temperature rises, arc extinguishment becomes more difficult, the switching capacity declines, and contact corrosion worsens. At rated load, contact adhesion is likely to occur; at moderate currents, carbides tend to form, reducing contact reliability.

But most of those I’ve encountered are single do

For the on-site electrical control panel, the start/stop buttons should be separate entities, and the control signals for the instruments should also be separated. The poster can take a look at the secondary electrical schematic. DO cardboards are relatively inexpensive, especially those with 16 or 32 points. @jiaguoyun

If you have local/remote switching, dual drives are necessary; otherwise, a seamless switch cannot be achieved.

It is highly recommended to use two-point control; otherwise, there will be an excessive reliance on the DCS intermediate relays.

We usually use 2 DOs; the \"on\" state is pulsed, the relay is generally not powered, and the \"on\" command is a \"1\" pulse signal. Moreover, the DO for “stop” often has an interlock function, allowing the motor to remain in operation, usually while it is under voltage ； And when the motor is not allowed to operate, it is uncharged. So the stop signal is sometimes a “0” pulse (allowing the motor to run), and sometimes a “0” state (interlock, no need for the motor to run).

I totally agree with what was said on the 2nd floor! ! ! ! ! ! ! ! ! ! ! ! !

I usually use dual-drive systems, as they are safe and stable.