Flexible Support for Any System
Mercer Controls provides programming, configuration, and troubleshooting support for PLC, SCADA, and HMI systems across water and wastewater facilities. Whether your system is decades old or newly installed, we can work with it.
We support all major PLC and SCADA platforms and can step in to modify, repair, or improve existing systems — even if we didn’t install them.
Programming, Modifications & Upgrades
Our services include:
- PLC programming and logic changes
- SCADA and HMI screen updates and improvements
- Alarm tuning and system optimization
- New system setup and commissioning
- Legacy system support and modernization
We focus on clear, operator-friendly systems that are easier to understand and maintain.
Communications & Telemetry Troubleshooting
If your system can’t communicate, it can’t protect your operation. We diagnose and repair:
- Radio and cellular telemetry
- SCADA communications issues
- Network and data transmission problems
- Intermittent or unreliable connections
Our team identifies the root cause and restores reliable communication.
When the Original Integrator Is Gone
The most common call we get about PLC work is not a new project. It is a utility running logic somebody else wrote years ago, on a processor that is no longer made, with no printout and no way to reach the person who built it. Everything works until the day it does not.
- The program exists only inside the processor, and nobody has a copy
- The processor is obsolete and spares are getting hard to find
- The logic was never documented, so nobody knows why a timer is set where it is
- The original integrator locked the program, went out of business, or simply will not return the call
- Changes have been layered on for fifteen years until nobody trusts any of it
We work on systems we did not build — that is most of what we do. See repairs and replacements.
If Nobody Has a Copy of Your Program, Fix That First
A PLC program is the only place a great deal of operational knowledge still lives: the alternation logic, the setpoints, the interlocks that stop two pumps running a well dry. If the processor fails and there is no backup, none of that comes back. It gets rebuilt from scratch, from memory, under pressure, while the plant is down.
Knowing where your program is backed up, and when it was last pulled, is a five minute question. If the answer is “nowhere”, that is the cheapest problem on this page to solve.
What Usually Prompts the Call
- Alarms flooding overnight that nobody can turn off
- Pumps that are supposed to alternate and do not
- A tank filling while SCADA shows no change
- An HMI screen nobody can read or trust
- A PLC sitting in fault, or a processor that will not go to run
- Communication errors between the plant and an outlying site
- A setpoint that needs changing and nobody willing to touch it
- A new well, lift station or meter to add to an existing system
Operator-Friendly Beats Clever
A system only its programmer understands is a liability. We write logic and lay out screens so the person on shift at two in the morning can tell what is happening, what tripped and what to do next — plain alarm text instead of a fault code, screens arranged the way the plant is actually arranged, and setpoints where an operator can find them.
If your crew inherited a system nobody ever explained, operator training covers the same ground from the other direction.
Support You Can Rely On
Cities rely on Mercer Controls because we are willing and able to work on any system, any platform, and any manufacturer’s equipment. We solve problems, improve performance, and keep operators in control.
To request programming or SCADA support, contact us today.
📞 (361) 782-7168