the left diagram is for Mechanical Differential Pressure Switch
The right diagram is for Electronic Differential Pressure Switch
Mechanical DPS only could output a SPDT signal, but Electronic DPS could output 2 DPS, but it need power supply.
Contact: Mr. Chou
Phone: 13166369204 (wechat)
Tel: 400-852-8332
Email: shanghai@ayite.net
Add: 17 &22, No.2928, Chuan Zhou Highway, Shanghai, 201319, China