Rhombus Services

We are Proud to be SJE!

At SJE, we are more than a company — we are a family of brands with a shared vision and mission to provide industry-leading, innovative, and reliable control and monitoring solutions that improve efficiencies, protect the environment, and deliver dependable solutions to our valued customers. We are looking for a Senior Edge Engineer to help build the next generation engineering team for our AMI Global brand. This role may work remote, but we would prefer a candidate to be near one of our SJE locations.

Our AMI brand is a leading IoT connectivity solution for equipment via hardware, SaaS, and software. Its gateways and cloud connected solutions enable real-time monitoring, control, analytics, and commercialization support. We provide integration, development, and go-to-market services. Check us out at AMI Global!

The job:

As our Senior Edge Engineer, you will be the team’s depth on bare-metal firmware. Day-to-day that means secure boot, signed firmware, MQTT-over-TLS to the cloud, and the field-side protocol layer (Modbus RTU, plus CAN bus where required) on our current ARM Cortex-M class device. You will work into the team’s embedded-Linux track as our next-generation gateway platform comes online. You will provide occasional mentorship of early-career engineers on cross functional firmware teams within the organization.

Your primary responsibilities will be:

• Security uplift on the current device platform: Secure boot, signed firmware images, hardware-rooted key storage (a secure-element companion or equivalent), verified OTA.
• A time-boxed feasibility study on cloud protocol: We need to know whether MQTT-over-TLS with mutual auth fits on the existing MCU: footprint, RAM/flash budget, TLS-stack viability. Your finding drives the platform’s edge-protocol decision.
• The field-side protocol layer: Modbus RTU primary, CAN bus where required. Clean driver abstraction so adding a new field protocol is additive rather than a fork.
• OTA strategy and safety: Bench validation, staged rollouts, rollback, recover. We engineer OTA carefully because a bricked device in a wastewater plant is a contractual problem, not just an inconvenience.
• Provisioning and identity: Per-device mutal-TLS credentials, secure key injection at manufacturing, key rotation.

The skills, education, and experience you need:

To succeed in this role, you must have experience with:

• Reading Modbus RTU timing diagrams on an oscilloscope
• Debugging a stuck mutual-TLS handshake on a constrained MCU
• Pulling a bricked unit back over JTAG
• NXP toolchains (hands-on) or equivalent vendor environments
• Production work on secure boot chains, signed firmware, and verified OTA on resource-constrained devices
• Integrating hardware secure elements (Microchip ATECC608, Infineon OPTIGA Trust, or similar)
• TLS/MQTT on constrained MCUs: mbedTLS, WolfSSL, or comparable
• Modbus RTU on bare metal: RS-485 driver, interrupt timing, framing
• Working at the bench: oscilloscope, logic analyzer, JTAG/SWD debug, signal-level diagnosis
• Embedded firmware (7+ years), fluency in C and modern C++ on ARM Cortex-M class microcontrollers

Bonus qualifications:

• CAN bus on bare metal
• Industrial cert experience (FCC, CE, UL)
• Manufacturing text fixture or test program design
• Industrial or critical-infrastructure deployment experience
• Yocto, Buildroot, or other embedded-Linux exposure

A 4-year degree in Computer Engineering, Computer Science, Electrical Engineering or equivalent degree and 7-10 years of experience are required.

Answering your questions:

When you are considering a new job, it is normal to have a ton of questions. Here are a few questions we are asked all the time.

• What are the hours? Monday – Friday 8:00 am – 5:00 pm.
• What is your Paid Time Off and holiday policy? Up to 120 hours of Paid Time Off in your first year plus 8 paid holidays.
• What benefits do you offer? We offer a robust benefits package including health, life, short-term and long-term disability insurance as well as dental and vision programs you need to take care of your family, along with other benefit options. Check out our full benefits package!
• What is my commute? Check out our SJE locations: SJE Locations

We will answer more of your questions during the first interview. Expect to hear about the next steps if you meet the job requirements.

Why Work With Us
At SJE, we believe in empowering our employees to grow professionally while making a real impact. We offer competitive pay, excellent benefits, and a collaborative culture that encourages creativity and problem-solving. Join us and become a part of something bigger. Join a company where you’re not just working—you’re building a legacy!

Learn more and apply on-line at www.sjeinc.com. SJE is an Equal Opportunity Employer.