Relay unit, control method for relay unit

Patent metadata

Field	Value
Publication number	US-9939491-B2
Application number	US-201514882534-A
Country	US
Kind code	B2
Filing date	Oct 14, 2015
Priority date	Feb 2, 2015
Publication date	Apr 10, 2018
Grant date	Apr 10, 2018

Abstract

The reliability of testing a normally closed contact in a relay unit may involve the following. Sending a first test signal to the first normally closed contact and detecting a return state of the first test signal sent, sending a second test signal different from the first test signal to the second normally closed contact and detecting a return state of the second test signal sent; and assessing an abnormality when at least one of the detection result for the return state of the first test signal does not satisfy a first predetermined criteria, and the detection result of the return state of the second test signal does not satisfy a second predetermined criteria different from the first predetermined criteria.

First claim

The invention claimed is:

1. A relay unit comprising:
a switching circuit comprising first and second normally open contacts and first and second normally closed contacts; and
a controller; wherein
the switching circuit:
in a state of de-energizing a load, the first and second normally open contacts are open and the first and second normally closed contacts are closed; and,
in a state of energizing the load, the first and second normally open contacts are closed and the first and second normally closed contacts are open;

the controller is configured with a program to perform operations comprising:
sending a first test signal to the first normally closed contact and detecting a return state of the first test signal;
sending a second test signal different from the first test signal to the second normally closed contact and detecting a return state of the second test signal; and
assessing the return state of the first and the return state of the second test signal as abnormal when at least one of:
the return state of the first test signal does not satisfy a first predetermined criteria, and
the return state of the second test signal does not satisfy a second predetermined criteria different from the first predetermined criteria;

the first test signal and the second test signal are pulse signals; and
at least one of: a period of the first test signal and the second test signal; a duty cycle of the first test signal and the second test signal; and a number of pulses within a fixed interval of the first test signal and the second test signal are mutually different.

2. The relay unit according to claim 1 , wherein the controller assesses the return state of the first test signal and the return state of the second test signal as normal when the result of detecting the return state of the first test signal satisfies the first predetermined criteria, and the result of detecting the return state of the second test signal satisfies the second predetermined criteria.

3. The relay unit according to claim 1 , wherein
the first predetermined criteria is satisfied when the period of the returning first test signal is between a first lower limit threshold and a first upper limit threshold inclusive; and
the second predetermined criteria is satisfied when the period of the returning second test signal is between a second lower limit threshold and a second upper limit threshold inclusive.

4. The relay unit according to claim 1 , wherein
the first predetermined criteria is satisfied when the number of pulses of the returning first test signal within a fixed interval is between a first lower limit threshold and a first upper limit threshold, inclusive; and
the second predetermined criteria is satisfied when the number of pulses of the returning second test signal within a fixed interval is between a second lower limit threshold and a second upper limit threshold, inclusive.

5. The relay unit according to claim 1 , wherein
the first predetermined criteria is satisfied when the duty cycle of the returning first test signal is between a first lower limit threshold and a first upper limit threshold, inclusive; and
the second predetermined criteria is satisfied when the duty cycle of the returning second test signal is between a second lower limit threshold and a second upper limit threshold, inclusive.

6. The relay unit according to claim 1 , wherein
the switching unit includes third and fourth normally open contacts, and third and fourth normally closed contacts;
the switching circuit:
in a state of de-energizing the load, the third and fourth normally open contacts are open and the third and fourth normally closed contacts are closed; and
in a state of energizing the load, the third and fourth normally open contacts are closed and the third and fourth normally closed contacts are open;

when the load is de-energized, the first and third normally closed contacts are connected, and the second and fourth normally closed contacts are connected; and
the first test signal returns to the controller via the first and third normally closed contacts, and the second test signal returns to the controller via the second and fourth normally closed contacts.

7. The relay unit according to claim 6 , wherein
the load and a load power source are connected in series between the first normally open contact and the third normally open contact; and
a second load different from the load and the load power source are connected in series between the second normally open contact and the fourth normally open contact.

8. A control method for a relay unit, the relay unit comprising:
a switching circuit comprising first and second normally open contacts and first and second normally closed contacts; and
a controller; wherein
the switching circuit:
in a state of de-energizing a load, the first and second normally open contacts are open and the first and second normally closed contacts are closed; and
in a state of energizing the load, the first and second normally open contacts are closed and the first and second normally closed contacts are open;

the control method comprising:
sending a first test signal to the first normally closed contact and detecting a return state of the first test signal;
sending a second test signal different from the first test signal to the second normally closed contact and detecting a return state of the second test signal; and
assessing the return state of the first and the return state of the second test signal as abnormal when at least one of the result of detecting the return state of the first test signal does not satisfy a first predetermined criteria, and the result of detecting the return state of the second test signal does not satisfy a second predetermined criteria different from the first predetermined criteria; wherein
the first test signal and the second test signal are pulse signals, and
at least one of: a period of the first test signal and the second test signal; a duty cycle of the first test signal and the second test signal; and a number of pulses within a fixed interval of the first test signal and the second test signal are mutually different.

9. The method according to claim 8 , further comprising:
assessing the first return state and the second return states as normal when the result of detecting the return state of the first test signal satisfies the first predetermined criteria, and the result of detecting return state of the returning second test signal satisfies the second predetermined criteria.

10. The method according to claim 8 , wherein
the first predetermined criteria is satisfied when the period of the returning first test signal is between a first lower limit threshold and a first upper limit threshold, inclusive; and
the second predetermined criteria is satisfied when whether period of the returning second test signal is between a second lower limit threshold and a second upper limit threshold, inclusive.

11. The method of claim 8 , wherein
the first predetermined criteria is satisfied when the number of pulses of the returning first test signal within a fixed interval is between a first lower limit threshold and a first upper limit threshold, inclusive; and
the second predetermined criteria is satisfied when the number of pulses of the returning second test signal within a fixed interval is between a second lower limit threshold and a second upper limit threshold, inclusive.

12. The method of claim 8 , wherein
the first predetermined criteria is satisfied when the duty cycle of the returning first test signal is between a first lower limit threshold and a first upper limit threshold, inclusive; and

Assignees

• Omron Tateisi Electronics Co

Inventors

• Fukumoto Tetsuya
• Higuchi Toshiyuki
• Murakami Kohei
• Fujii Satoshi

Classifications

• H01H47/002 Primary

  Monitoring or fail-safe circuits · CPC title

• G01R31/3278 Primary

  of relays, solenoids or reed switches (measuring contact resistance G01R27/205; high voltage magnetic switches G01R31/3271, G01R31/333; testing electric windings G01R31/72; monitoring of fail safe circuits H01H47/002) · CPC title

• H01H50/16

  Magnetic circuit arrangements · CPC title

• H01H47/004

  using plural redundant serial connected relay operated contacts in controlled circuit · CPC title