The MR-J3ENCBL2M-B1-H is Mitsubishi Electric’s 2-metre heavy-duty flexible encoder cable with B1-type motor-side connector for connecting MR-J4 and MR-J3 series servo amplifiers to HG-SR, HG-RR, and equivalent servo motors equipped with the B1-type encoder connector — the B1-connector variant of the 2-metre heavy-duty flex encoder cable, designed for servo motor models whose encoder connector uses the B1 physical interface rather than the A1 connector used by the majority of HG-series motors. Atlantech Drives holds stock of the MR-J3ENCBL2M-B1-H. Contact us for fast worldwide delivery and competitive pricing.
What Is the MR-J3ENCBL2M-B1-H?
The MR-J3ENCBL2M-B1-H is a Mitsubishi Electric servo encoder cable from the MR-J3ENCBL series, providing the same 2-metre heavy-duty flex encoder cable function as the MR-J3ENCBL2M-A1-H but with a B1-type motor-side connector in place of the A1-type. The B1 connector designation identifies a physically different motor encoder connector housing used on specific HG-SR and HG-RR series motor frame sizes — typically the larger-frame motor models where the motor body dimensions accommodate a different connector mounting configuration than the compact A1 connector. The amplifier-side connector is identical between A1-H and B1-H variants — the standard 20-pin MIL CN2 connector compatible with all MR-J4 and MR-J3 series servo amplifiers. Both the A1-H and B1-H cables transmit the same 22-bit absolute encoder serial data between motor and amplifier — the connector type difference is purely physical (mechanical mating interface) and has no effect on the encoder signal protocol, resolution, or communication cycle. The heavy-duty «H» construction provides the same flex cycle rating as the MR-J3ENCBL2M-A1-H — individually shielded pairs with stranded conductors and an outer jacket suitable for energy chain installation in moving axis applications.
Key Technical Specifications
- Model: MR-J3ENCBL2M-B1-H
- Cable Length: 2 metres
- Motor-Side Connector: B1-type (specific HG-SR, HG-RR larger-frame motor encoder connector)
- Amplifier-Side Connector: MR-J3/J4 CN2 20-pin MIL circular connector
- Construction: Heavy-duty flex (H) — rated for moving axis / energy chain installation
- Signal Type: Serial encoder (22-bit absolute, MR-J4/J3 proprietary protocol)
- Compatible Amplifiers: MR-J4-A, MR-J4-B, MR-J3-A, MR-J3-B series (all power ratings)
- Compatible Motors: HG-SR, HG-RR series models with B1-type encoder connector (verify per motor model)
- Shielding: Individual pair shielding + overall braid shield
- Operating Temperature: -20°C to 70°C
- Minimum Bend Radius: Per Mitsubishi flex cable specification
Series Comparison & Selection Guide
Within the MR-J3ENCBL 2-metre heavy-duty flex encoder cable range, the sole difference between the MR-J3ENCBL2M-A1-H and the MR-J3ENCBL2M-B1-H is the motor-side connector type — A1 versus B1. The A1 connector is used by the majority of HG-KR, HG-MR, HG-SR, and HG-RR motors in the small-to-medium frame size range (typically 100 W through 2 kW frame sizes). The B1 connector is used by specific larger-frame HG-SR and HG-RR motor models — the exact motor models requiring the B1 connector are listed in the Mitsubishi MELSERVO-J4 servo motor connector compatibility table in the MR-J4 servo amplifier instruction manual and the HG-SR/HG-RR hardware manual. The correct selection between A1-H and B1-H is determined entirely by the motor model being connected — check the specific motor model’s encoder connector type designation in the motor hardware manual before ordering. Using the incorrect connector type (A1 cable on a B1 motor, or vice versa) results in a cable that physically cannot be mated to the motor’s encoder connector — there is no risk of incorrect electrical connection, as the connectors are mechanically keyed and cannot be forced together. For any given servo motor, only one of the A1 or B1 connector types is correct — the motor hardware manual specifies which cable variant to order for each motor model.
Troubleshooting Guide
If a newly installed MR-J3ENCBL2M-B1-H generates an immediate AL.16 (encoder error) alarm on first servo-on, the most likely causes are connector seating and cable-to-motor model compatibility. First verify that the B1 motor-side connector is fully mated and the locking mechanism (locking ring or latch clip depending on the specific B1 connector variant) is fully engaged — a partially mated B1 connector causes all encoder pins to be out of contact, generating immediate AL.16 at servo-on. If the connector is fully mated and AL.16 persists, verify that the motor model requires the B1 connector (not the A1) by checking the motor’s hardware manual connector compatibility table — ordering the A1 cable for a B1 motor is a common procurement error that results in a cable that cannot be physically connected to the motor, not in an electrical fault. For intermittent AL.16 alarms that appear after initial successful servo operation, inspect the B1 motor-side connector for signs of connector fretting corrosion — on moving axis installations, the connector body experiences small relative movements between the mated connectors due to cable tension variation during axis travel, causing fretting wear on the connector pin contact surfaces over time. If fretting corrosion is suspected, apply a small amount of electrical contact lubricant (Nyogel 760G or equivalent) to the B1 connector pins and re-mate the connector — if the intermittent AL.16 clears, confirm the diagnosis and plan for connector replacement at the next maintenance interval.
Frequently Asked Questions
Q: How do I determine whether my HG-SR servo motor requires the A1-H or B1-H encoder cable?
A: Check the motor model number against the encoder cable compatibility table in the MR-J4 servo amplifier instruction manual (specifically the «Connection of Servo Motor» section) or in the HG-SR series hardware manual’s connector specification table. The table lists each motor model with its corresponding cable variant (A1 or B1). As a general guide, smaller-frame HG-SR models (100 W through approximately 2 kW) typically use A1, while larger-frame models may use B1 — but always verify against the official table rather than relying on frame size generalisation.
Q: Can the MR-J3ENCBL2M-B1-H be extended to reach a motor more than 2 metres from the amplifier?
A: Encoder cable extension using field-made splices or inline connectors is not recommended for 22-bit serial encoder signals — any splice introduces additional contact resistance and potential signal reflection that can corrupt the high-speed serial encoder data. If 2 metres is insufficient for the installation, order the correct length cable from Mitsubishi’s catalogue (MR-J3ENCBL5M-B1-H for 5 metres, or other available lengths) rather than extending the 2-metre cable. The maximum cable length between amplifier and motor is specified in the servo amplifier instruction manual — exceeding this limit degrades encoder signal quality and may cause intermittent or persistent AL.16 alarms.
Q: Is the B1 connector on the MR-J3ENCBL2M-B1-H IP65 rated when fully mated?
A: Yes. The B1 motor-side connector on the MR-J3ENCBL2M-B1-H provides IP65 protection when fully mated to the motor’s encoder connector — the connector housing includes sealing gaskets that compress between the mated connector bodies when the locking mechanism is fully engaged. If the locking ring or latch is not fully engaged, the IP65 sealing is not achieved and moisture can enter the connector interface. Always confirm full locking engagement after connector mating in environments where water splash or coolant mist exposure is present.
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