This checklist covers the two VM600 proximity probe part numbers most often ordered for rotating machinery protection: TQ402 111-402-000-012/013 and TQ412 111-412-000-012/013. Use it before you place an order, replace a probe on site, or confirm a spare part list.
1. Confirm the complete part number first
Do not order only TQ402 or TQ412. The suffix -012 or -013 can change cable length, connector type, or probe body option.
Record the full number from the old probe label. If the label is missing, check the system BOM or the signal conditioner channel configuration.
Check these items:
- TQ402 111-402-000-012 or 111-402-000-013
- TQ412 111-412-000-012 or 111-412-000-013
- Extension cable EA402 913-402-000-012 or 913-402-000-013
- Signal conditioner IQS450 channel type
2. Mechanical fit checklist
TQ402 and TQ412 are not automatically interchangeable. Verify mechanical fit before ordering.
Check:
- Probe tip diameter
- Thread size and pitch
- Probe body length
- Mounting hole condition in the machine case
- Target surface width and material
If the probe does not seat correctly or touches the target, the gap voltage will be wrong and the channel may trip falsely.
3. Cable and connector checklist
Check the probe integral cable and extension cable as one system.
- Integral cable length from probe to junction box
- EA402 extension cable length and connector type
- Cable shield and jacket condition
- No field splice on the probe cable
A damaged extension cable can cause signal drift. Do not repair with electrical tape or a non-shielded splice. Replace with the correct EA402 length.
4. Signal chain checklist
The probe alone does not provide a usable output. It must match the signal conditioner input.
Verify:
- IQS450 input sensitivity setting
- Static gap voltage before machine start
- Target material and plating
- Probe sensitivity code vs system calibration
If the probe, extension cable, or signal conditioner suffix changes, recalibrate the channel before returning to service.
5. Pre-order verification table
Use this table before you confirm an order.
| Item | What to check | Wrong result if not checked |
|---|---|---|
| Part number suffix | -012 vs -013 | Cable too short or connector mismatch |
| Probe tip and thread | Measure with caliper or drawing | Probe does not seat or touches target |
| Extension cable | EA402 length and connector | Signal loss or sensitivity mismatch |
| Gap voltage | Verify DC gap reading at static position | False trip or channel alarm |
| Target surface | Clean metal, no heavy scoring or plating change | Incorrect gap reading and drift |
| Environment | Temperature and moisture rating | Probe failure or unstable signal |
6. Common ordering mistakes
Avoid these errors:
- Ordering TQ402 when the machine uses TQ412
- Mixing -012 and -013 cable lengths without checking the junction box location
- Replacing only the probe when the EA402 extension cable is also damaged
- Changing target material without recalibration
- Using a probe with the wrong thread and forcing it into the mounting hole
- Assuming TQ402 and TQ412 have the same measurement range
7. Final check before shipment
Before you send the PO or confirm stock, complete this list:
- Full part number and quantity
- Photo of the old probe label and connector
- Target material if the target has been changed
- Cable length required from probe to junction box
- Signal conditioner model and channel count
- Required delivery date
FAQ
Are TQ402 111-402-000-012 and TQ412 111-412-000-012 interchangeable?
Not by default. Probe selection depends on tip diameter, measurement range, and machine design. Check the drawing or old label first.
What does suffix 012 or 013 mean?
It usually indicates cable length or connector option. Always match the existing installation, or update the extension cable and signal conditioner setting together.
Can I replace only the probe if the extension cable is damaged?
Inspect the full chain first. If only the EA402 extension cable is damaged, replace EA402. If the probe coil or integral cable is damaged, replace TQ402 or TQ412.
What if I only know the old short number, not the full 111-402-000-012/013 code?
Send a photo of the old label or the system drawing to the supplier. The full part number can be matched from the probe head, thread, cable length, and connector.
Contact for stock and compatibility check
Joyoung International Trading Co., Limited stocks TQ402 111-402-000-012/013, TQ412 111-412-000-012/013, EA402 extension cables, IQS450 signal conditioners, and related VM600 rack cards.
Send your full part number and quantity to [email protected] or call +86-181-5013-7565. We confirm suffix, cable length, and compatibility before quotation.
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