SPDT Relay Controlling Fwd/Rev Solenoids

[JackPW]

If I have my PLC output driving a SPDT relay, is there any downside for that relay to control both directional solenoids on a hydraulic valve connected to a cylinder?
Specifically, could the immediate switching have detrimental effects on the relay, solenoid, or valve? should I use one relay for each solenoid with a short delay between? if so, why?
I could use a single solenoid with a spring return but I'm working with existing config.

Thanks in advance

 

[mass89]

Dont see any reason why not, no need for a delay unless your syatem needs it for process reasons. Bare in mind, using 1 spdt for both valve directions would mean loss of power to the relay because of control issue or estop press would cause the cylinder possibly to move when not desired. Usually what i see is spring centered directional valve and 2 separate relays.

 

[James Mcquade]

First and foremost.

1. what is the application and what does that cylinder do?

2. if you loose power to the relay and the hydraulics keep running, what will happen when the relay causes the valve to shift?

3. what does your risk assessment tell you?

you MUST ask what if questions. if you cannot answer the question, you MUST find the answer!

in my opinion, you have asked a question without giving a lot of required details. there are too many unknows.

james

 

[JackPW]

Thank you for the reply. I am only interested in any mechanical or electrical degradation associated with this configuration. The process is assumed to be correct

 

[GaryS]

one down side is that one of the solenoids will be energizes all the time it could over heat the solenoid if you have the I/O would use 2 outputs with a relay on each
Power off the solenoid closes cylinder stops all motion